21564234 has 12 divisors (see below), whose sum is σ = 46722546. Its totient is φ = 7188072.

The previous prime is 21564227. The next prime is 21564239. The reversal of 21564234 is 43246512.

21564234 is a `hidden beast` number, since 2 + 15 + 642 + 3 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 11923209 + 9641025 = 3453^2 + 3105^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21564198 and 21564207.

It is not an unprimeable number, because it can be changed into a prime (21564239) 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, 598989 + ... + 599024.

Almost surely, 2^21564234 is an apocalyptic number.

21564234 is an abundant number, since it is smaller than the sum of its proper divisors (25158312).

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

21564234 is a wasteful number, since it uses less digits than its factorization.

21564234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1198021 (or 1198018 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 21564234 is about 4643.7306123418. The cubic root of 21564234 is about 278.3415311469.

The spelling of 21564234 in words is "twenty-one million, five hundred sixty-four thousand, two hundred thirty-four".