21881275236 has 18 divisors (see below), whose sum is σ = 55311001382. Its totient is φ = 7293758400.

The previous prime is 21881275231. The next prime is 21881275237. The reversal of 21881275236 is 63257218812.

21881275236 is a `hidden beast` number, since 21 + 8 + 81 + 27 + 523 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 20349022500 + 1532252736 = 142650^2 + 39144^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a junction number, because it is equal to n+sod(n) for n = 21881275191 and 21881275200.

It is not an unprimeable number, because it can be changed into a prime (21881275231) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 303906565 + ... + 303906636.

Almost surely, 2^21881275236 is an apocalyptic number.

It is an amenable number.

21881275236 is an abundant number, since it is smaller than the sum of its proper divisors (33429726146).

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

21881275236 is a wasteful number, since it uses less digits than its factorization.

21881275236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 607813211 (or 607813206 counting only the distinct ones).

The product of its digits is 322560, while the sum is 45.

The spelling of 21881275236 in words is "twenty-one billion, eight hundred eighty-one million, two hundred seventy-five thousand, two hundred thirty-six".