21251011836 has 48 divisors (see below), whose sum is σ = 50829327360. Its totient is φ = 6907131840.

The previous prime is 21251011813. The next prime is 21251011889. The reversal of 21251011836 is 63811015212.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 81681 + ... + 221751.

It is an arithmetic number, because the mean of its divisors is an integer number (1058944320).

Almost surely, 2^21251011836 is an apocalyptic number.

It is an amenable number.

21251011836 is an abundant number, since it is smaller than the sum of its proper divisors (29578315524).

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

21251011836 is a wasteful number, since it uses less digits than its factorization.

21251011836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140394 (or 140392 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The spelling of 21251011836 in words is "twenty-one billion, two hundred fifty-one million, eleven thousand, eight hundred thirty-six".