20717969 has 2 divisors, whose sum is σ = 20717970. Its totient is φ = 20717968.

The previous prime is 20717953. The next prime is 20717989. The reversal of 20717969 is 96971702.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19536400 + 1181569 = 4420^2 + 1087^2 .

It is a cyclic number.

It is not a de Polignac number, because 20717969 - 2⁴ = 20717953 is a prime.

It is a super-2 number, since 2×20717969² = 858468478969922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20717989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10358984 + 10358985.

It is an arithmetic number, because the mean of its divisors is an integer number (10358985).

Almost surely, 2^20717969 is an apocalyptic number.

It is an amenable number.

20717969 is a deficient number, since it is larger than the sum of its proper divisors (1).

20717969 is an equidigital number, since it uses as much as digits as its factorization.

20717969 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 47628, while the sum is 41.

The square root of 20717969 is about 4551.6995726871. The cubic root of 20717969 is about 274.6517641696.

The spelling of 20717969 in words is "twenty million, seven hundred seventeen thousand, nine hundred sixty-nine".