991390117 has 8 divisors (see below), whose sum is σ = 1014900320. Its totient is φ = 968114160.

The previous prime is 991390063. The next prime is 991390123. The reversal of 991390117 is 711093199.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991390117 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 991390117.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991390187) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49983 + ... + 66940.

It is an arithmetic number, because the mean of its divisors is an integer number (126862540).

Almost surely, 2^991390117 is an apocalyptic number.

It is an amenable number.

991390117 is a deficient number, since it is larger than the sum of its proper divisors (23510203).

991390117 is a wasteful number, since it uses less digits than its factorization.

991390117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117123.

The product of its (nonzero) digits is 15309, while the sum is 40.

The square root of 991390117 is about 31486.3481051709. The cubic root of 991390117 is about 997.1217626980.

The spelling of 991390117 in words is "nine hundred ninety-one million, three hundred ninety thousand, one hundred seventeen".