21256107400 has 48 divisors (see below), whose sum is σ = 53913223440. Its totient is φ = 7729492800.

The previous prime is 21256107371. The next prime is 21256107401. The reversal of 21256107400 is 470165212.

It is not an unprimeable number, because it can be changed into a prime (21256107401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4828734 + ... + 4833133.

It is an arithmetic number, because the mean of its divisors is an integer number (1123192155).

Almost surely, 2^21256107400 is an apocalyptic number.

21256107400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21256107400 is an abundant number, since it is smaller than the sum of its proper divisors (32657116040).

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

21256107400 is a wasteful number, since it uses less digits than its factorization.

21256107400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9661894 (or 9661885 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 28.

The spelling of 21256107400 in words is "twenty-one billion, two hundred fifty-six million, one hundred seven thousand, four hundred".