157691917 has 2 divisors, whose sum is σ = 157691918. Its totient is φ = 157691916.

The previous prime is 157691857. The next prime is 157691929. The reversal of 157691917 is 719196751.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 119115396 + 38576521 = 10914^2 + 6211^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-157691917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157691987) 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, 78845958 + 78845959.

It is an arithmetic number, because the mean of its divisors is an integer number (78845959).

Almost surely, 2^157691917 is an apocalyptic number.

It is an amenable number.

157691917 is a deficient number, since it is larger than the sum of its proper divisors (1).

157691917 is an equidigital number, since it uses as much as digits as its factorization.

157691917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 119070, while the sum is 46.

The square root of 157691917 is about 12557.5442264800. The cubic root of 157691917 is about 540.2604105215.

The spelling of 157691917 in words is "one hundred fifty-seven million, six hundred ninety-one thousand, nine hundred seventeen".