20664013 has 2 divisors, whose sum is σ = 20664014. Its totient is φ = 20664012.

The previous prime is 20663989. The next prime is 20664023. The reversal of 20664013 is 31046602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18992164 + 1671849 = 4358^2 + 1293^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20664013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20664023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10332006 + 10332007.

It is an arithmetic number, because the mean of its divisors is an integer number (10332007).

Almost surely, 2^20664013 is an apocalyptic number.

It is an amenable number.

20664013 is a deficient number, since it is larger than the sum of its proper divisors (1).

20664013 is an equidigital number, since it uses as much as digits as its factorization.

20664013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 20664013 is about 4545.7686918716. The cubic root of 20664013 is about 274.4131308404.

The spelling of 20664013 in words is "twenty million, six hundred sixty-four thousand, thirteen".