991944078 has 32 divisors (see below), whose sum is σ = 2070647712. Its totient is φ = 316492800.

The previous prime is 991944059. The next prime is 991944089. The reversal of 991944078 is 870449199.

It is a self number, because there is not a number n which added to its sum of digits gives 991944078.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25003 + ... + 51078.

It is an arithmetic number, because the mean of its divisors is an integer number (64707741).

Almost surely, 2^991944078 is an apocalyptic number.

991944078 is an abundant number, since it is smaller than the sum of its proper divisors (1078703634).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991944078 is a wasteful number, since it uses less digits than its factorization.

991944078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76180.

The product of its (nonzero) digits is 653184, while the sum is 51.

The square root of 991944078 is about 31495.1437208977. The cubic root of 991944078 is about 997.3074493445.

The spelling of 991944078 in words is "nine hundred ninety-one million, nine hundred forty-four thousand, seventy-eight".