21672579 has 16 divisors (see below), whose sum is σ = 29399040. Its totient is φ = 14199840.

The previous prime is 21672571. The next prime is 21672583. The reversal of 21672579 is 97527612.

It is not a de Polignac number, because 21672579 - 2³ = 21672571 is a prime.

It is a super-2 number, since 2×21672579² = 939401361022482, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21672571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 62284 + ... + 62630.

It is an arithmetic number, because the mean of its divisors is an integer number (1837440).

Almost surely, 2^21672579 is an apocalyptic number.

21672579 is a deficient number, since it is larger than the sum of its proper divisors (7726461).

21672579 is a wasteful number, since it uses less digits than its factorization.

21672579 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 650.

The product of its digits is 52920, while the sum is 39.

The square root of 21672579 is about 4655.3817244132. The cubic root of 21672579 is about 278.8069089570.

The spelling of 21672579 in words is "twenty-one million, six hundred seventy-two thousand, five hundred seventy-nine".