21120255012 has 24 divisors (see below), whose sum is σ = 49294980000. Its totient is φ = 7038030016.

The previous prime is 21120255007. The next prime is 21120255041. The reversal of 21120255012 is 21055202112.

It is a super-2 number, since 2×21120255012² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21120255012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 213762 + ... + 296537.

It is an arithmetic number, because the mean of its divisors is an integer number (2053957500).

Almost surely, 2^21120255012 is an apocalyptic number.

It is an amenable number.

21120255012 is an abundant number, since it is smaller than the sum of its proper divisors (28174724988).

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

21120255012 is a wasteful number, since it uses less digits than its factorization.

21120255012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513755 (or 513753 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 21.

Adding to 21120255012 its reverse (21055202112), we get a palindrome (42175457124).

The spelling of 21120255012 in words is "twenty-one billion, one hundred twenty million, two hundred fifty-five thousand, twelve".