172581157 has 4 divisors (see below), whose sum is σ = 197235616. Its totient is φ = 147926700.

The previous prime is 172581131. The next prime is 172581163. The reversal of 172581157 is 751185271.

It is a happy number.

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: 751185271 = 53 ⋅14173307.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172581157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172581107) 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 in 3 ways as a sum of consecutive naturals, for example, 12327219 + ... + 12327232.

It is an arithmetic number, because the mean of its divisors is an integer number (49308904).

Almost surely, 2^172581157 is an apocalyptic number.

It is an amenable number.

172581157 is a deficient number, since it is larger than the sum of its proper divisors (24654459).

172581157 is an equidigital number, since it uses as much as digits as its factorization.

172581157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24654458.

The product of its digits is 19600, while the sum is 37.

The square root of 172581157 is about 13137.0147674424. The cubic root of 172581157 is about 556.7554266217.

The spelling of 172581157 in words is "one hundred seventy-two million, five hundred eighty-one thousand, one hundred fifty-seven".