21565163234 has 4 divisors (see below), whose sum is σ = 32347744854. Its totient is φ = 10782581616.

The previous prime is 21565163209. The next prime is 21565163281. The reversal of 21565163234 is 43236156512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 15864158209 + 5701005025 = 125953^2 + 75505^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5391290807 + ... + 5391290810.

Almost surely, 2^21565163234 is an apocalyptic number.

21565163234 is a deficient number, since it is larger than the sum of its proper divisors (10782581620).

21565163234 is a wasteful number, since it uses less digits than its factorization.

21565163234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10782581619.

The product of its digits is 129600, while the sum is 38.

The spelling of 21565163234 in words is "twenty-one billion, five hundred sixty-five million, one hundred sixty-three thousand, two hundred thirty-four".