21304371636 has 36 divisors (see below), whose sum is σ = 55308199492. Its totient is φ = 6909525504.

The previous prime is 21304371631. The next prime is 21304371637. The reversal of 21304371636 is 63617340312.

21304371636 is a `hidden beast` number, since 2 + 13 + 0 + 4 + 3 + 7 + 1 + 636 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14582011536 + 6722360100 = 120756^2 + 81990^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21304371636.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304371631) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7995805 + ... + 7998468.

Almost surely, 2^21304371636 is an apocalyptic number.

It is an amenable number.

21304371636 is an abundant number, since it is smaller than the sum of its proper divisors (34003827856).

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

21304371636 is a wasteful number, since it uses less digits than its factorization.

21304371636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15994320 (or 15994315 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 36.

The spelling of 21304371636 in words is "twenty-one billion, three hundred four million, three hundred seventy-one thousand, six hundred thirty-six".