990917997120 has 672 divisors, whose sum is σ = 3604874232960. Its totient is φ = 259044065280.

The previous prime is 990917997109. The next prime is 990917997211. The reversal of 990917997120 is 21799719099.

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, 906603294 + ... + 906604386.

It is an arithmetic number, because the mean of its divisors is an integer number (5364396180).

Almost surely, 2^990917997120 is an apocalyptic number.

990917997120 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 990917997120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1802437116480).

990917997120 is an abundant number, since it is smaller than the sum of its proper divisors (2613956235840).

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

990917997120 is a wasteful number, since it uses less digits than its factorization.

990917997120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1345 (or 1323 counting only the distinct ones).

The product of its (nonzero) digits is 5786802, while the sum is 63.

The spelling of 990917997120 in words is "nine hundred ninety billion, nine hundred seventeen million, nine hundred ninety-seven thousand, one hundred twenty".