91720172152571 has 8 divisors (see below), whose sum is σ = 92411781701520. Its totient is φ = 91028883172608.

The previous prime is 91720172152561. The next prime is 91720172152601. The reversal of 91720172152571 is 17525127102719.

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 91720172152571 - 2¹⁸ = 91720171890427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91720172152561) 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, 79567841 + ... + 80712338.

It is an arithmetic number, because the mean of its divisors is an integer number (11551472712690).

Almost surely, 2^{91720172152571} is an apocalyptic number.

91720172152571 is a deficient number, since it is larger than the sum of its proper divisors (691609548949).

91720172152571 is a wasteful number, since it uses less digits than its factorization.

91720172152571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160284493.

The product of its (nonzero) digits is 617400, while the sum is 50.

The spelling of 91720172152571 in words is "ninety-one trillion, seven hundred twenty billion, one hundred seventy-two million, one hundred fifty-two thousand, five hundred seventy-one".