20156710657 has 2 divisors, whose sum is σ = 20156710658. Its totient is φ = 20156710656.

The previous prime is 20156710591. The next prime is 20156710667. The reversal of 20156710657 is 75601765102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13512667536 + 6644043121 = 116244^2 + 81511^2 .

It is a cyclic number.

It is not a de Polignac number, because 20156710657 - 2¹¹ = 20156708609 is a prime.

It is not a weakly prime, because it can be changed into another prime (20156710667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10078355328 + 10078355329.

It is an arithmetic number, because the mean of its divisors is an integer number (10078355329).

Almost surely, 2^20156710657 is an apocalyptic number.

It is an amenable number.

20156710657 is a deficient number, since it is larger than the sum of its proper divisors (1).

20156710657 is an equidigital number, since it uses as much as digits as its factorization.

20156710657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 88200, while the sum is 40.

The spelling of 20156710657 in words is "twenty billion, one hundred fifty-six million, seven hundred ten thousand, six hundred fifty-seven".