621861027840 has 1080 divisors, whose sum is σ = 2437797955320. Its totient is φ = 151353556992.

The previous prime is 621861027833. The next prime is 621861027847. The reversal of 621861027840 is 48720168126.

621861027840 is a `hidden beast` number, since 6 + 2 + 1 + 8 + 610 + 27 + 8 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (621861027833) and next prime (621861027847).

It can be written as a sum of positive squares in 4 ways, for example, as 967458816 + 620893569024 = 31104^2 + 787968^2 .

It is a tau number, because it is divible by the number of its divisors (1080).

It is a super-2 number, since 2×621861027840² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (621861027847) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 6987202516 + ... + 6987202604.

It is an arithmetic number, because the mean of its divisors is an integer number (2257220329).

Almost surely, 2^621861027840 is an apocalyptic number.

621861027840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 621861027840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1218898977660).

621861027840 is an abundant number, since it is smaller than the sum of its proper divisors (1815936927480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

621861027840 is an frugal number, since it uses more digits than its factorization.

621861027840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159 (or 112 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

It can be divided in two parts, 62186 and 1027840, that added together give a triangular number (1090026 = T₁₄₇₆).

The spelling of 621861027840 in words is "six hundred twenty-one billion, eight hundred sixty-one million, twenty-seven thousand, eight hundred forty".