20569657 has 2 divisors, whose sum is σ = 20569658. Its totient is φ = 20569656.

The previous prime is 20569649. The next prime is 20569667. The reversal of 20569657 is 75696502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12752041 + 7817616 = 3571^2 + 2796^2 .

It is a cyclic number.

It is not a de Polignac number, because 20569657 - 2³ = 20569649 is a prime.

It is a super-2 number, since 2×20569657² = 846221578195298, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20569667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10284828 + 10284829.

It is an arithmetic number, because the mean of its divisors is an integer number (10284829).

Almost surely, 2^20569657 is an apocalyptic number.

It is an amenable number.

20569657 is a deficient number, since it is larger than the sum of its proper divisors (1).

20569657 is an equidigital number, since it uses as much as digits as its factorization.

20569657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 113400, while the sum is 40.

The square root of 20569657 is about 4535.3783745130. The cubic root of 20569657 is about 273.9948184858.

The spelling of 20569657 in words is "twenty million, five hundred sixty-nine thousand, six hundred fifty-seven".