991113131 has 8 divisors (see below), whose sum is σ = 1068723600. Its totient is φ = 916047360.

The previous prime is 991113089. The next prime is 991113139. The reversal of 991113131 is 131311199.

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 991113131 - 2¹⁰ = 991112107 is a prime.

It is a super-2 number, since 2×991113131² = 1964610476881246322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 991113094 and 991113103.

It is not an unprimeable number, because it can be changed into a prime (991113139) 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, 635366 + ... + 636923.

It is an arithmetic number, because the mean of its divisors is an integer number (133590450).

Almost surely, 2^991113131 is an apocalyptic number.

991113131 is a deficient number, since it is larger than the sum of its proper divisors (77610469).

991113131 is a wasteful number, since it uses less digits than its factorization.

991113131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1272349.

The product of its digits is 729, while the sum is 29.

The square root of 991113131 is about 31481.9492884415. The cubic root of 991113131 is about 997.0288915906.

The spelling of 991113131 in words is "nine hundred ninety-one million, one hundred thirteen thousand, one hundred thirty-one".