21615322120 has 32 divisors (see below), whose sum is σ = 55582257600. Its totient is φ = 7410967488.

The previous prime is 21615322117. The next prime is 21615322121. The reversal of 21615322120 is 2122351612.

It is a super-2 number, since 2×21615322120² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21615322121) 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 7 ways as a sum of consecutive naturals, for example, 38598510 + ... + 38599069.

It is an arithmetic number, because the mean of its divisors is an integer number (1736945550).

Almost surely, 2^21615322120 is an apocalyptic number.

21615322120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21615322120 is an abundant number, since it is smaller than the sum of its proper divisors (33966935480).

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

21615322120 is a wasteful number, since it uses less digits than its factorization.

21615322120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77197597 (or 77197593 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

Adding to 21615322120 its reverse (2122351612), we get a palindrome (23737673732).

The spelling of 21615322120 in words is "twenty-one billion, six hundred fifteen million, three hundred twenty-two thousand, one hundred twenty".