991390118 has 16 divisors (see below), whose sum is σ = 1507222080. Its totient is φ = 488993856.

The previous prime is 991390063. The next prime is 991390123. The reversal of 991390118 is 811093199.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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, 256730 + ... + 260562.

It is an arithmetic number, because the mean of its divisors is an integer number (94201380).

Almost surely, 2^991390118 is an apocalyptic number.

991390118 is a deficient number, since it is larger than the sum of its proper divisors (515831962).

991390118 is a wasteful number, since it uses less digits than its factorization.

991390118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5551.

The product of its (nonzero) digits is 17496, while the sum is 41.

The square root of 991390118 is about 31486.3481210508. The cubic root of 991390118 is about 997.1217630333.

The spelling of 991390118 in words is "nine hundred ninety-one million, three hundred ninety thousand, one hundred eighteen".