991814959 has 4 divisors (see below), whose sum is σ = 991984504. Its totient is φ = 991645416.

The previous prime is 991814951. The next prime is 991814981. The reversal of 991814959 is 959418199.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 991814959 - 2³ = 991814951 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991814951) 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 3 ways as a sum of consecutive naturals, for example, 75672 + ... + 87805.

It is an arithmetic number, because the mean of its divisors is an integer number (247996126).

Almost surely, 2^991814959 is an apocalyptic number.

991814959 is a deficient number, since it is larger than the sum of its proper divisors (169545).

991814959 is a wasteful number, since it uses less digits than its factorization.

991814959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169544.

The product of its digits is 1049760, while the sum is 55.

The square root of 991814959 is about 31493.0938302352. The cubic root of 991814959 is about 997.2641750877.

The spelling of 991814959 in words is "nine hundred ninety-one million, eight hundred fourteen thousand, nine hundred fifty-nine".