172188331561 has 4 divisors (see below), whose sum is σ = 172193676624. Its totient is φ = 172182986500.

The previous prime is 172188331547. The next prime is 172188331591. The reversal of 172188331561 is 165133881271.

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 a cyclic number.

It is not a de Polignac number, because 172188331561 - 2⁷ = 172188331433 is a prime.

It is a super-3 number, since 3×172188331561³ (a number of 35 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172188331591) 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, 2623915 + ... + 2688736.

It is an arithmetic number, because the mean of its divisors is an integer number (43048419156).

Almost surely, 2^172188331561 is an apocalyptic number.

It is an amenable number.

172188331561 is a deficient number, since it is larger than the sum of its proper divisors (5345063).

172188331561 is an equidigital number, since it uses as much as digits as its factorization.

172188331561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5345062.

The product of its digits is 241920, while the sum is 46.

The spelling of 172188331561 in words is "one hundred seventy-two billion, one hundred eighty-eight million, three hundred thirty-one thousand, five hundred sixty-one".