851172891 has 16 divisors (see below), whose sum is σ = 1201922304. Its totient is φ = 534672864.

The previous prime is 851172871. The next prime is 851172913. The reversal of 851172891 is 198271158.

It is not a de Polignac number, because 851172891 - 2⁹ = 851172379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (851172821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87436 + ... + 96681.

It is an arithmetic number, because the mean of its divisors is an integer number (75120144).

Almost surely, 2^851172891 is an apocalyptic number.

851172891 is a deficient number, since it is larger than the sum of its proper divisors (350749413).

851172891 is a wasteful number, since it uses less digits than its factorization.

851172891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184210.

The product of its digits is 40320, while the sum is 42.

The square root of 851172891 is about 29174.8674547118. The cubic root of 851172891 is about 947.7037398327.

The spelling of 851172891 in words is "eight hundred fifty-one million, one hundred seventy-two thousand, eight hundred ninety-one".