171899750891 has 18 divisors (see below), whose sum is σ = 192275448876. Its totient is φ = 152410972800.

The previous prime is 171899750863. The next prime is 171899750921. The reversal of 171899750891 is 198057998171.

It is a de Polignac number, because none of the positive numbers 2^k-171899750891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (171899750851) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 56377535 + ... + 56380583.

It is an arithmetic number, because the mean of its divisors is an integer number (10681969382).

Almost surely, 2^171899750891 is an apocalyptic number.

171899750891 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

171899750891 is a deficient number, since it is larger than the sum of its proper divisors (20375697985).

171899750891 is an frugal number, since it uses more digits than its factorization.

171899750891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6191 (or 3101 counting only the distinct ones).

The product of its (nonzero) digits is 11430720, while the sum is 65.

The spelling of 171899750891 in words is "one hundred seventy-one billion, eight hundred ninety-nine million, seven hundred fifty thousand, eight hundred ninety-one".