172491897 has 4 divisors (see below), whose sum is σ = 229989200. Its totient is φ = 114994596.

The previous prime is 172491883. The next prime is 172491923. The reversal of 172491897 is 798194271.

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.

It is not a de Polignac number, because 172491897 - 2²² = 168297593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172491827) 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, 28748647 + ... + 28748652.

It is an arithmetic number, because the mean of its divisors is an integer number (57497300).

Almost surely, 2^172491897 is an apocalyptic number.

It is an amenable number.

172491897 is a deficient number, since it is larger than the sum of its proper divisors (57497303).

172491897 is an equidigital number, since it uses as much as digits as its factorization.

172491897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57497302.

The product of its digits is 254016, while the sum is 48.

The square root of 172491897 is about 13133.6170570030. The cubic root of 172491897 is about 556.6594243304.

The spelling of 172491897 in words is "one hundred seventy-two million, four hundred ninety-one thousand, eight hundred ninety-seven".