991399575699456 has 2880 divisors, whose sum is σ = 3685396279541760. Its totient is φ = 230954316595200.

The previous prime is 991399575699361. The next prime is 991399575699503. The reversal of 991399575699456 is 654996575993199.

It is a super-2 number, since 2×991399575699456² (a number of 31 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (96).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1601614823115 + ... + 1601614823733.

It is an arithmetic number, because the mean of its divisors is an integer number (1279651485952).

Almost surely, 2^{991399575699456} is an apocalyptic number.

991399575699456 is a gapful number since it is divisible by the number (96) 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 991399575699456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1842698139770880).

991399575699456 is an abundant number, since it is smaller than the sum of its proper divisors (2693996703842304).

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

991399575699456 is a wasteful number, since it uses less digits than its factorization.

991399575699456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800 (or 763 counting only the distinct ones).

The product of its digits is 200884698000, while the sum is 96.

The spelling of 991399575699456 in words is "nine hundred ninety-one trillion, three hundred ninety-nine billion, five hundred seventy-five million, six hundred ninety-nine thousand, four hundred fifty-six".