21156261570 has 48 divisors (see below), whose sum is σ = 55182092472. Its totient is φ = 5623637760.

The previous prime is 21156261559. The next prime is 21156261583. The reversal of 21156261570 is 7516265112.

21156261570 is a `hidden beast` number, since 2 + 1 + 15 + 626 + 15 + 7 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 9038875329 + 12117386241 = 95073^2 + 110079^2 .

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 347341 + ... + 403680.

Almost surely, 2^21156261570 is an apocalyptic number.

21156261570 is an abundant number, since it is smaller than the sum of its proper divisors (34025830902).

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

21156261570 is a wasteful number, since it uses less digits than its factorization.

21156261570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751347 (or 751344 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 21156261570 in words is "twenty-one billion, one hundred fifty-six million, two hundred sixty-one thousand, five hundred seventy".