21629579 has 2 divisors, whose sum is σ = 21629580. Its totient is φ = 21629578.

The previous prime is 21629561. The next prime is 21629617. The reversal of 21629579 is 97592612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21629579 - 2²⁰ = 20581003 is a prime.

It is not a weakly prime, because it can be changed into another prime (21629519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10814789 + 10814790.

It is an arithmetic number, because the mean of its divisors is an integer number (10814790).

Almost surely, 2^21629579 is an apocalyptic number.

21629579 is a deficient number, since it is larger than the sum of its proper divisors (1).

21629579 is an equidigital number, since it uses as much as digits as its factorization.

21629579 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 21629579 is about 4650.7611205049. The cubic root of 21629579 is about 278.6223956963.

The spelling of 21629579 in words is "twenty-one million, six hundred twenty-nine thousand, five hundred seventy-nine".