155917 has 4 divisors (see below), whose sum is σ = 162720. Its totient is φ = 149116.

The previous prime is 155893. The next prime is 155921. The reversal of 155917 is 719551.

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: 719551 = 7 ⋅102793.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155917 is a prime.

It is a super-2 number, since 2×155917² = 48620221778, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

155917 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3367 + ... + 3412.

It is an arithmetic number, because the mean of its divisors is an integer number (40680).

2¹⁵⁵⁹¹⁷ is an apocalyptic number.

It is an amenable number.

155917 is a deficient number, since it is larger than the sum of its proper divisors (6803).

155917 is an equidigital number, since it uses as much as digits as its factorization.

155917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6802.

The product of its digits is 1575, while the sum is 28.

The square root of 155917 is about 394.8632674737. The cubic root of 155917 is about 53.8225772766.

The spelling of 155917 in words is "one hundred fifty-five thousand, nine hundred seventeen".