21564514 has 4 divisors (see below), whose sum is σ = 32346774. Its totient is φ = 10782256.

The previous prime is 21564511. The next prime is 21564523. The reversal of 21564514 is 41546512.

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., 21390625 + 173889 = 4625^2 + 417^2 .

It is not an unprimeable number, because it can be changed into a prime (21564511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5391127 + ... + 5391130.

Almost surely, 2^21564514 is an apocalyptic number.

21564514 is a deficient number, since it is larger than the sum of its proper divisors (10782260).

21564514 is a wasteful number, since it uses less digits than its factorization.

21564514 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10782259.

The product of its digits is 4800, while the sum is 28.

The square root of 21564514 is about 4643.7607604182. The cubic root of 21564514 is about 278.3427358468.

It can be divided in two parts, 2156 and 4514, that added together give a triangular number (6670 = T₁₁₅).

The spelling of 21564514 in words is "twenty-one million, five hundred sixty-four thousand, five hundred fourteen".