21900856236 has 48 divisors (see below), whose sum is σ = 61476092160. Its totient is φ = 5928050880.

The previous prime is 21900856213. The next prime is 21900856253. The reversal of 21900856236 is 63265800912.

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 6859575 + ... + 6862766.

It is an arithmetic number, because the mean of its divisors is an integer number (1280751920).

Almost surely, 2^21900856236 is an apocalyptic number.

It is an amenable number.

21900856236 is an abundant number, since it is smaller than the sum of its proper divisors (39575235924).

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

21900856236 is a wasteful number, since it uses less digits than its factorization.

21900856236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13722374 (or 13722372 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The spelling of 21900856236 in words is "twenty-one billion, nine hundred million, eight hundred fifty-six thousand, two hundred thirty-six".