991922490720 has 576 divisors, whose sum is σ = 4085359649280. Its totient is φ = 214093062144.

The previous prime is 991922490679. The next prime is 991922490737. The reversal of 991922490720 is 27094229199.

It is a super-2 number, since 2×991922490720² (a number of 25 digits) contains 22 as substring.

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, 59937487 + ... + 59954033.

It is an arithmetic number, because the mean of its divisors is an integer number (7092638280).

Almost surely, 2^991922490720 is an apocalyptic number.

991922490720 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 991922490720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2042679824640).

991922490720 is an abundant number, since it is smaller than the sum of its proper divisors (3093437158560).

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

991922490720 is a wasteful number, since it uses less digits than its factorization.

991922490720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16907 (or 16896 counting only the distinct ones).

The product of its (nonzero) digits is 1469664, while the sum is 54.

The spelling of 991922490720 in words is "nine hundred ninety-one billion, nine hundred twenty-two million, four hundred ninety thousand, seven hundred twenty".