990756665640 has 512 divisors, whose sum is σ = 3954275942400. Its totient is φ = 215879178240.

The previous prime is 990756665617. The next prime is 990756665659. The reversal of 990756665640 is 46566657099.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 15670572 + ... + 15733668.

It is an arithmetic number, because the mean of its divisors is an integer number (7723195200).

Almost surely, 2^990756665640 is an apocalyptic number.

990756665640 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 990756665640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1977137971200).

990756665640 is an abundant number, since it is smaller than the sum of its proper divisors (2963519276760).

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

990756665640 is a wasteful number, since it uses less digits than its factorization.

990756665640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63222 (or 63212 counting only the distinct ones).

The product of its (nonzero) digits is 73483200, while the sum is 63.

The spelling of 990756665640 in words is "nine hundred ninety billion, seven hundred fifty-six million, six hundred sixty-five thousand, six hundred forty".