21907847858724 has 81 divisors (see below), whose sum is σ = 55510311544051. Its totient is φ = 7285232271360.

The previous prime is 21907847858653. The next prime is 21907847858759. The reversal of 21907847858724 is 42785874870912.

The square root of 21907847858724 is 4680582.

It is a perfect power (a square), and thus also a powerful number.

21907847858724 is a `hidden beast` number, since 2 + 1 + 9 + 0 + 78 + 478 + 5 + 87 + 2 + 4 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1920081348900 + 19987766509824 = 1385670^2 + 4470768^2 .

It is a Duffinian 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 26 ways as a sum of consecutive naturals, for example, 18001517764 + ... + 18001518980.

Almost surely, 2^{21907847858724} is an apocalyptic number.

21907847858724 is the 4680582-nd square number.

It is an amenable number.

21907847858724 is an abundant number, since it is smaller than the sum of its proper divisors (33602463685327).

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

21907847858724 is an frugal number, since it uses more digits than its factorization.

21907847858724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3726 (or 1863 counting only the distinct ones).

The product of its (nonzero) digits is 505774080, while the sum is 72.

The spelling of 21907847858724 in words is "twenty-one trillion, nine hundred seven billion, eight hundred forty-seven million, eight hundred fifty-eight thousand, seven hundred twenty-four".