991711944 has 64 divisors (see below), whose sum is σ = 2764728000. Its totient is φ = 329374080.

The previous prime is 991711939. The next prime is 991711951. The reversal of 991711944 is 449117199.

It is a self number, because there is not a number n which added to its sum of digits gives 991711944.

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, 52527 + ... + 68865.

It is an arithmetic number, because the mean of its divisors is an integer number (43198875).

Almost surely, 2^991711944 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991711944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1382364000).

991711944 is an abundant number, since it is smaller than the sum of its proper divisors (1773016056).

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

991711944 is a wasteful number, since it uses less digits than its factorization.

991711944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16635 (or 16625 counting only the distinct ones).

The product of its digits is 81648, while the sum is 45.

The square root of 991711944 is about 31491.4582704580. The cubic root of 991711944 is about 997.2296468977.

The spelling of 991711944 in words is "nine hundred ninety-one million, seven hundred eleven thousand, nine hundred forty-four".