891115715991 has 8 divisors (see below), whose sum is σ = 1190488581360. Its totient is φ = 592909997312.

The previous prime is 891115715953. The next prime is 891115715999. The reversal of 891115715991 is 199517511198.

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

It is a cyclic number.

It is not a de Polignac number, because 891115715991 - 2⁷ = 891115715863 is a prime.

It is a super-2 number, since 2×891115715991² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891115715999) 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, 291784890 + ... + 291787943.

It is an arithmetic number, because the mean of its divisors is an integer number (148811072670).

Almost surely, 2^891115715991 is an apocalyptic number.

891115715991 is a deficient number, since it is larger than the sum of its proper divisors (299372865369).

891115715991 is a wasteful number, since it uses less digits than its factorization.

891115715991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 583573345.

The product of its digits is 1020600, while the sum is 57.

The spelling of 891115715991 in words is "eight hundred ninety-one billion, one hundred fifteen million, seven hundred fifteen thousand, nine hundred ninety-one".