991921167 has 32 divisors (see below), whose sum is σ = 1519810560. Its totient is φ = 638729280.

The previous prime is 991921141. The next prime is 991921187. The reversal of 991921167 is 761129199.

It is not a de Polignac number, because 991921167 - 2⁶ = 991921103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991921187) 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, 691483 + ... + 692915.

It is an arithmetic number, because the mean of its divisors is an integer number (47494080).

Almost surely, 2^991921167 is an apocalyptic number.

991921167 is a deficient number, since it is larger than the sum of its proper divisors (527889393).

991921167 is a wasteful number, since it uses less digits than its factorization.

991921167 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2300 (or 2294 counting only the distinct ones).

The product of its digits is 61236, while the sum is 45.

The square root of 991921167 is about 31494.7799960565. The cubic root of 991921167 is about 997.2997709926.

The spelling of 991921167 in words is "nine hundred ninety-one million, nine hundred twenty-one thousand, one hundred sixty-seven".