157997 has 4 divisors (see below), whose sum is σ = 180576. Its totient is φ = 135420.

The previous prime is 157991. The next prime is 157999. The reversal of 157997 is 799751.

157997 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 799751 = 433 ⋅1847.

It is a cyclic number.

It is not a de Polignac number, because 157997 - 2⁶ = 157933 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 157997.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 157997.

It is not an unprimeable number, because it can be changed into a prime (157991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11279 + ... + 11292.

It is an arithmetic number, because the mean of its divisors is an integer number (45144).

2¹⁵⁷⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

157997 is a deficient number, since it is larger than the sum of its proper divisors (22579).

157997 is an equidigital number, since it uses as much as digits as its factorization.

157997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22578.

The product of its digits is 19845, while the sum is 38.

The square root of 157997 is about 397.4883646096. The cubic root of 157997 is about 54.0608595958.

The spelling of 157997 in words is "one hundred fifty-seven thousand, nine hundred ninety-seven".