21526979 has 2 divisors, whose sum is σ = 21526980. Its totient is φ = 21526978.

The previous prime is 21526951. The next prime is 21527021. The reversal of 21526979 is 97962512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21526979 - 2²⁴ = 4749763 is a prime.

It is not a weakly prime, because it can be changed into another prime (21526579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10763489 + 10763490.

It is an arithmetic number, because the mean of its divisors is an integer number (10763490).

Almost surely, 2^21526979 is an apocalyptic number.

21526979 is a deficient number, since it is larger than the sum of its proper divisors (1).

21526979 is an equidigital number, since it uses as much as digits as its factorization.

21526979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 41.

The square root of 21526979 is about 4639.7175560588. The cubic root of 21526979 is about 278.1811484333.

The spelling of 21526979 in words is "twenty-one million, five hundred twenty-six thousand, nine hundred seventy-nine".