173997561 has 4 divisors (see below), whose sum is σ = 231996752. Its totient is φ = 115998372.

The previous prime is 173997547. The next prime is 173997587. The reversal of 173997561 is 165799371.

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: 165799371 = 3 ⋅55266457.

It is not a de Polignac number, because 173997561 - 2⁵ = 173997529 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 173997561.

It is not an unprimeable number, because it can be changed into a prime (173997541) 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, 28999591 + ... + 28999596.

It is an arithmetic number, because the mean of its divisors is an integer number (57999188).

Almost surely, 2^173997561 is an apocalyptic number.

It is an amenable number.

173997561 is a deficient number, since it is larger than the sum of its proper divisors (57999191).

173997561 is an equidigital number, since it uses as much as digits as its factorization.

173997561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57999190.

The product of its digits is 357210, while the sum is 48.

The square root of 173997561 is about 13190.8135078925. The cubic root of 173997561 is about 558.2744086524.

The spelling of 173997561 in words is "one hundred seventy-three million, nine hundred ninety-seven thousand, five hundred sixty-one".