991380580320 has 576 divisors, whose sum is σ = 3674522880000. Its totient is φ = 223719874560.

The previous prime is 991380580313. The next prime is 991380580327. The reversal of 991380580320 is 23085083199.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (991380580313) and next prime (991380580327).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 991380580320.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991380580327) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 47769306 + ... + 47790054.

It is an arithmetic number, because the mean of its divisors is an integer number (6379380000).

Almost surely, 2^991380580320 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 991380580320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1837261440000).

991380580320 is an abundant number, since it is smaller than the sum of its proper divisors (2683142299680).

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

991380580320 is a wasteful number, since it uses less digits than its factorization.

991380580320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20843 (or 20822 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 48.

The spelling of 991380580320 in words is "nine hundred ninety-one billion, three hundred eighty million, five hundred eighty thousand, three hundred twenty".