991488325365720 has 1024 divisors, whose sum is σ = 4282820591616000. Its totient is φ = 198132542208000.

The previous prime is 991488325365697. The next prime is 991488325365743. The reversal of 991488325365720 is 27563523884199.

991488325365720 is a `hidden beast` number, since 9 + 9 + 1 + 4 + 8 + 8 + 32 + 536 + 57 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (991488325365697) and next prime (991488325365743).

It is a super-2 number, since 2×991488325365720² (a number of 31 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 7564447785 + ... + 7564578855.

It is an arithmetic number, because the mean of its divisors is an integer number (4182441984000).

It is a 2-persistent number, because it is pandigital, and so is 2⋅991488325365720 = 1982976650731440, but 3⋅991488325365720 = 2974464976097160 is not.

Almost surely, 2^{991488325365720} is an apocalyptic number.

991488325365720 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 991488325365720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2141410295808000).

991488325365720 is an abundant number, since it is smaller than the sum of its proper divisors (3291332266250280).

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

991488325365720 is a wasteful number, since it uses less digits than its factorization.

991488325365720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135181 (or 135171 counting only the distinct ones).

The product of its (nonzero) digits is 783820800, while the sum is 72.

The spelling of 991488325365720 in words is "nine hundred ninety-one trillion, four hundred eighty-eight billion, three hundred twenty-five million, three hundred sixty-five thousand, seven hundred twenty".