21803916906864 has 50 divisors (see below), whose sum is σ = 63106861359960. Its totient is φ = 7267972301856.

The previous prime is 21803916906859. The next prime is 21803916906887. The reversal of 21803916906864 is 46860961930812.

21803916906864 is a `hidden beast` number, since 2 + 1 + 80 + 391 + 6 + 90 + 6 + 86 + 4 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 8412003684 + ... + 8412006275.

Almost surely, 2^{21803916906864} is an apocalyptic number.

21803916906864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21803916906864 is an abundant number, since it is smaller than the sum of its proper divisors (41302944453096).

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

21803916906864 is a wasteful number, since it uses less digits than its factorization.

21803916906864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16824009979 (or 16824009964 counting only the distinct ones).

The product of its (nonzero) digits is 26873856, while the sum is 63.

The spelling of 21803916906864 in words is "twenty-one trillion, eight hundred three billion, nine hundred sixteen million, nine hundred six thousand, eight hundred sixty-four".