21679506 has 24 divisors (see below), whose sum is σ = 47112780. Its totient is φ = 7204896.

The previous prime is 21679477. The next prime is 21679561. The reversal of 21679506 is 60597612.

It can be written as a sum of positive squares in 2 ways, for example, as 21538881 + 140625 = 4641^2 + 375^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5100 + ... + 8328.

Almost surely, 2^21679506 is an apocalyptic number.

21679506 is an abundant number, since it is smaller than the sum of its proper divisors (25433274).

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

21679506 is a wasteful number, since it uses less digits than its factorization.

21679506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3610 (or 3607 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 21679506 is about 4656.1256426347. The cubic root of 21679506 is about 278.8366099251.

It can be divided in two parts, 2167 and 9506, that multiplied together give a palindrome (20599502).

The spelling of 21679506 in words is "twenty-one million, six hundred seventy-nine thousand, five hundred six".