21639783636 has 24 divisors (see below), whose sum is σ = 56103143040. Its totient is φ = 7213261176.

The previous prime is 21639783593. The next prime is 21639783653. The reversal of 21639783636 is 63638793612.

21639783636 is a `hidden beast` number, since 216 + 397 + 8 + 3 + 6 + 36 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 100184076 + ... + 100184291.

It is an arithmetic number, because the mean of its divisors is an integer number (2337630960).

Almost surely, 2^21639783636 is an apocalyptic number.

It is an amenable number.

21639783636 is an abundant number, since it is smaller than the sum of its proper divisors (34463359404).

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

21639783636 is a wasteful number, since it uses less digits than its factorization.

21639783636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200368380 (or 200368372 counting only the distinct ones).

The product of its digits is 5878656, while the sum is 54.

The spelling of 21639783636 in words is "twenty-one billion, six hundred thirty-nine million, seven hundred eighty-three thousand, six hundred thirty-six".