157170991 has 2 divisors, whose sum is σ = 157170992. Its totient is φ = 157170990.

The previous prime is 157170947. The next prime is 157170997. The reversal of 157170991 is 199071751.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 157170991 - 2¹⁷ = 157039919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157170997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78585495 + 78585496.

It is an arithmetic number, because the mean of its divisors is an integer number (78585496).

Almost surely, 2^157170991 is an apocalyptic number.

157170991 is a deficient number, since it is larger than the sum of its proper divisors (1).

157170991 is an equidigital number, since it uses as much as digits as its factorization.

157170991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19845, while the sum is 40.

The square root of 157170991 is about 12536.7855130412. The cubic root of 157170991 is about 539.6648480432.

The spelling of 157170991 in words is "one hundred fifty-seven million, one hundred seventy thousand, nine hundred ninety-one".