1861608840 has 256 divisors, whose sum is σ = 6913105920. Its totient is φ = 390528000.

The previous prime is 1861608839. The next prime is 1861608841. The reversal of 1861608840 is 488061681.

It is an interprime number because it is at equal distance from previous prime (1861608839) and next prime (1861608841).

It is a super-2 number, since 2×1861608840² = 6931174946332291200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 1861608792 and 1861608801.

It is not an unprimeable number, because it can be changed into a prime (1861608841) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2478465 + ... + 2479215.

It is an arithmetic number, because the mean of its divisors is an integer number (27004320).

Almost surely, 2^1861608840 is an apocalyptic number.

1861608840 is a gapful number since it is divisible by the number (10) 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 1861608840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3456552960).

1861608840 is an abundant number, since it is smaller than the sum of its proper divisors (5051497080).

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

1861608840 is a wasteful number, since it uses less digits than its factorization.

1861608840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1012 (or 1008 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 42.

The square root of 1861608840 is about 43146.3653162117. The cubic root of 1861608840 is about 1230.1634259684.

It can be divided in two parts, 186160 and 8840, that added together give a triangular number (195000 = T₆₂₄).

The spelling of 1861608840 in words is "one billion, eight hundred sixty-one million, six hundred eight thousand, eight hundred forty".