172991854871 has 32 divisors (see below), whose sum is σ = 202498781760. Its totient is φ = 147263079040.

The previous prime is 172991854859. The next prime is 172991854877. The reversal of 172991854871 is 178458199271.

It is a de Polignac number, because none of the positive numbers 2^k-172991854871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172991854877) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 878131145 + ... + 878131341.

It is an arithmetic number, because the mean of its divisors is an integer number (6328086930).

Almost surely, 2^172991854871 is an apocalyptic number.

172991854871 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

172991854871 is a deficient number, since it is larger than the sum of its proper divisors (29506926889).

172991854871 is an frugal number, since it uses more digits than its factorization.

172991854871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 641 (or 225 counting only the distinct ones).

The product of its digits is 10160640, while the sum is 62.

The spelling of 172991854871 in words is "one hundred seventy-two billion, nine hundred ninety-one million, eight hundred fifty-four thousand, eight hundred seventy-one".