172173491 has 4 divisors (see below), whose sum is σ = 196769712. Its totient is φ = 147577272.

The previous prime is 172173487. The next prime is 172173499. The reversal of 172173491 is 194371271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 194371271 = 31 ⋅6270041.

It is a cyclic number.

It is not a de Polignac number, because 172173491 - 2² = 172173487 is a prime.

It is a super-2 number, since 2×172173491² = 59287422006254162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172173499) 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, 12298100 + ... + 12298113.

It is an arithmetic number, because the mean of its divisors is an integer number (49192428).

Almost surely, 2^172173491 is an apocalyptic number.

172173491 is a deficient number, since it is larger than the sum of its proper divisors (24596221).

172173491 is an equidigital number, since it uses as much as digits as its factorization.

172173491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24596220.

The product of its digits is 10584, while the sum is 35.

The square root of 172173491 is about 13121.4896639063. The cubic root of 172173491 is about 556.3166973678.

The spelling of 172173491 in words is "one hundred seventy-two million, one hundred seventy-three thousand, four hundred ninety-one".