991710720 has 960 divisors, whose sum is σ = 4718697984. Its totient is φ = 185794560.

The previous prime is 991710697. The next prime is 991710737. The reversal of 991710720 is 27017199.

It is a tau number, because it is divible by the number of its divisors (960).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 23063019 + ... + 23063061.

Almost surely, 2^991710720 is an apocalyptic number.

991710720 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991710720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2359348992).

991710720 is an abundant number, since it is smaller than the sum of its proper divisors (3726987264).

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

991710720 is a wasteful number, since it uses less digits than its factorization.

991710720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103 (or 84 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 36.

The square root of 991710720 is about 31491.4388366108. The cubic root of 991710720 is about 997.2292366275.

The spelling of 991710720 in words is "nine hundred ninety-one million, seven hundred ten thousand, seven hundred twenty".