20975657 has 2 divisors, whose sum is σ = 20975658. Its totient is φ = 20975656.

The previous prime is 20975627. The next prime is 20975663. The reversal of 20975657 is 75657902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19545241 + 1430416 = 4421^2 + 1196^2 .

It is a cyclic number.

It is not a de Polignac number, because 20975657 - 2⁸ = 20975401 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20975627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10487828 + 10487829.

It is an arithmetic number, because the mean of its divisors is an integer number (10487829).

Almost surely, 2^20975657 is an apocalyptic number.

It is an amenable number.

20975657 is a deficient number, since it is larger than the sum of its proper divisors (1).

20975657 is an equidigital number, since it uses as much as digits as its factorization.

20975657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 132300, while the sum is 41.

The square root of 20975657 is about 4579.9188857446. The cubic root of 20975657 is about 275.7857724658.

The spelling of 20975657 in words is "twenty million, nine hundred seventy-five thousand, six hundred fifty-seven".