21064679 has 2 divisors, whose sum is σ = 21064680. Its totient is φ = 21064678.

The previous prime is 21064627. The next prime is 21064723. The reversal of 21064679 is 97646012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21064679 - 2²⁰ = 20016103 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21064079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10532339 + 10532340.

It is an arithmetic number, because the mean of its divisors is an integer number (10532340).

Almost surely, 2^21064679 is an apocalyptic number.

21064679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21064679 is an equidigital number, since it uses as much as digits as its factorization.

21064679 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 21064679 is about 4589.6273269188. The cubic root of 21064679 is about 276.1753725103.

The spelling of 21064679 in words is "twenty-one million, sixty-four thousand, six hundred seventy-nine".