172156891 has 8 divisors (see below), whose sum is σ = 181429200. Its totient is φ = 162905760.

The previous prime is 172156877. The next prime is 172156913. The reversal of 172156891 is 198651271.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 172156891 - 2⁹ = 172156379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172156801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13065 + ... + 22693.

It is an arithmetic number, because the mean of its divisors is an integer number (22678650).

Almost surely, 2^172156891 is an apocalyptic number.

172156891 is a deficient number, since it is larger than the sum of its proper divisors (9272309).

172156891 is an equidigital number, since it uses as much as digits as its factorization.

172156891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10589.

The product of its digits is 30240, while the sum is 40.

The square root of 172156891 is about 13120.8570985283. The cubic root of 172156891 is about 556.2988178171.

The spelling of 172156891 in words is "one hundred seventy-two million, one hundred fifty-six thousand, eight hundred ninety-one".