21204938853756 has 144 divisors (see below), whose sum is σ = 62400677364480. Its totient is φ = 5945954169600.

The previous prime is 21204938853743. The next prime is 21204938853781. The reversal of 21204938853756 is 65735883940212.

21204938853756 is a `hidden beast` number, since 2 + 1 + 2 + 0 + 4 + 93 + 8 + 8 + 537 + 5 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a junction number, because it is equal to n+sod(n) for n = 21204938853693 and 21204938853702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7749135 + ... + 10122201.

It is a 1-persistent number, because it is pandigital, but 2⋅21204938853756 = 42409877707512 is not.

Almost surely, 2^{21204938853756} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21204938853756, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31200338682240).

21204938853756 is an abundant number, since it is smaller than the sum of its proper divisors (41195738510724).

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

21204938853756 is a wasteful number, since it uses less digits than its factorization.

21204938853756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2373744 (or 2373739 counting only the distinct ones).

The product of its (nonzero) digits is 87091200, while the sum is 63.

The spelling of 21204938853756 in words is "twenty-one trillion, two hundred four billion, nine hundred thirty-eight million, eight hundred fifty-three thousand, seven hundred fifty-six".