21366537836 has 48 divisors (see below), whose sum is σ = 45050191872. Its totient is φ = 8673134400.

The previous prime is 21366537817. The next prime is 21366537859. The reversal of 21366537836 is 63873566312.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 221075 + ... + 302666.

It is an arithmetic number, because the mean of its divisors is an integer number (938545664).

Almost surely, 2^21366537836 is an apocalyptic number.

It is an amenable number.

21366537836 is an abundant number, since it is smaller than the sum of its proper divisors (23683654036).

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

21366537836 is a wasteful number, since it uses less digits than its factorization.

21366537836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523830 (or 523828 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 50.

The spelling of 21366537836 in words is "twenty-one billion, three hundred sixty-six million, five hundred thirty-seven thousand, eight hundred thirty-six".