21921268635 has 96 divisors (see below), whose sum is σ = 45967933440. Its totient is φ = 9450411264.

The previous prime is 21921268631. The next prime is 21921268657. The reversal of 21921268635 is 53686212912.

21921268635 is a `hidden beast` number, since 2 + 1 + 9 + 2 + 1 + 2 + 6 + 8 + 635 = 666.

It is not a de Polignac number, because 21921268635 - 2² = 21921268631 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21921268631) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 364902 + ... + 420708.

It is an arithmetic number, because the mean of its divisors is an integer number (478832640).

Almost surely, 2^21921268635 is an apocalyptic number.

21921268635 is an abundant number, since it is smaller than the sum of its proper divisors (24046664805).

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

21921268635 is a wasteful number, since it uses less digits than its factorization.

21921268635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55897 (or 55894 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The spelling of 21921268635 in words is "twenty-one billion, nine hundred twenty-one million, two hundred sixty-eight thousand, six hundred thirty-five".