991671567 has 8 divisors (see below), whose sum is σ = 1322749440. Its totient is φ = 660854040.

The previous prime is 991671539. The next prime is 991671599. The reversal of 991671567 is 765176199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 991671567 - 2⁸ = 991671311 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991671517) 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, 56017 + ... + 71562.

It is an arithmetic number, because the mean of its divisors is an integer number (165343680).

Almost surely, 2^991671567 is an apocalyptic number.

991671567 is a deficient number, since it is larger than the sum of its proper divisors (331077873).

991671567 is a wasteful number, since it uses less digits than its factorization.

991671567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130173.

The product of its digits is 714420, while the sum is 51.

The square root of 991671567 is about 31490.8171853320. The cubic root of 991671567 is about 997.2161128306.

The spelling of 991671567 in words is "nine hundred ninety-one million, six hundred seventy-one thousand, five hundred sixty-seven".