621243540 has 96 divisors (see below), whose sum is σ = 1936368000. Its totient is φ = 165355776.

The previous prime is 621243533. The next prime is 621243541. The reversal of 621243540 is 45342126.

621243540 is a `hidden beast` number, since 621 + 2 + 4 + 35 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621243541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 549696 + ... + 550824.

It is an arithmetic number, because the mean of its divisors is an integer number (20170500).

Almost surely, 2^621243540 is an apocalyptic number.

621243540 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 621243540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (968184000).

621243540 is an abundant number, since it is smaller than the sum of its proper divisors (1315124460).

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

621243540 is a wasteful number, since it uses less digits than its factorization.

621243540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2166 (or 2158 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 621243540 is about 24924.7575715392. The cubic root of 621243540 is about 853.2716084232.

Adding to 621243540 its reverse (45342126), we get a palindrome (666585666).

The spelling of 621243540 in words is "six hundred twenty-one million, two hundred forty-three thousand, five hundred forty".