20718697 has 2 divisors, whose sum is σ = 20718698. Its totient is φ = 20718696.

The previous prime is 20718689. The next prime is 20718701. The reversal of 20718697 is 79681702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17438976 + 3279721 = 4176^2 + 1811^2 .

It is a cyclic number.

It is not a de Polignac number, because 20718697 - 2³ = 20718689 is a prime.

It is not a weakly prime, because it can be changed into another prime (20718637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10359348 + 10359349.

It is an arithmetic number, because the mean of its divisors is an integer number (10359349).

Almost surely, 2^20718697 is an apocalyptic number.

It is an amenable number.

20718697 is a deficient number, since it is larger than the sum of its proper divisors (1).

20718697 is an equidigital number, since it uses as much as digits as its factorization.

20718697 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 20718697 is about 4551.7795421132. The cubic root of 20718697 is about 274.6549810895.

The spelling of 20718697 in words is "twenty million, seven hundred eighteen thousand, six hundred ninety-seven".