21872635236 has 45 divisors (see below), whose sum is σ = 55643578991. Its totient is φ = 7244439696.

The previous prime is 21872635231. The next prime is 21872635259. The reversal of 21872635236 is 63253627812.

The square root of 21872635236 is 147894.

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

21872635236 is a `hidden beast` number, since 2 + 1 + 8 + 7 + 2 + 635 + 2 + 3 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3744705636 + 18127929600 = 61194^2 + 134640^2 .

It is a Duffinian number.

Its product of digits (725760) is a multiple of the sum of its prime divisors (162).

It is a junction number, because it is equal to n+sod(n) for n = 21872635191 and 21872635200.

It is not an unprimeable number, because it can be changed into a prime (21872635231) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 139316070 + ... + 139316226.

Almost surely, 2^21872635236 is an apocalyptic number.

21872635236 is the 147894-th square number.

It is an amenable number.

21872635236 is an abundant number, since it is smaller than the sum of its proper divisors (33770943755).

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

21872635236 is an frugal number, since it uses more digits than its factorization.

21872635236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638 (or 162 counting only the distinct ones).

The product of its digits is 725760, while the sum is 45.

The spelling of 21872635236 in words is "twenty-one billion, eight hundred seventy-two million, six hundred thirty-five thousand, two hundred thirty-six".