991038430980 has 576 divisors, whose sum is σ = 3465058222080. Its totient is φ = 227252044800.

The previous prime is 991038430979. The next prime is 991038431003. The reversal of 991038430980 is 89034830199.

991038430980 is a `hidden beast` number, since 9 + 91 + 0 + 38 + 430 + 98 + 0 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1000038285 + ... + 1000039275.

It is an arithmetic number, because the mean of its divisors is an integer number (6015726080).

Almost surely, 2^991038430980 is an apocalyptic number.

991038430980 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 991038430980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1732529111040).

991038430980 is an abundant number, since it is smaller than the sum of its proper divisors (2474019791100).

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

991038430980 is a wasteful number, since it uses less digits than its factorization.

991038430980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1392 (or 1387 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 54.

The spelling of 991038430980 in words is "nine hundred ninety-one billion, thirty-eight million, four hundred thirty thousand, nine hundred eighty".