991759676544 has 1280 divisors, whose sum is σ = 3820964716800. Its totient is φ = 248314429440.

The previous prime is 991759676543. The next prime is 991759676587. The reversal of 991759676544 is 445676957199.

It is a happy number.

991759676544 is a `hidden beast` number, since 9 + 9 + 1 + 7 + 5 + 9 + 6 + 76 + 544 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (991759676543) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 1833196914 + ... + 1833197454.

It is an arithmetic number, because the mean of its divisors is an integer number (2985128685).

Almost surely, 2^991759676544 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 991759676544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1910482358400).

991759676544 is an abundant number, since it is smaller than the sum of its proper divisors (2829205040256).

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

991759676544 is a wasteful number, since it uses less digits than its factorization.

991759676544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683 (or 662 counting only the distinct ones).

The product of its digits is 514382400, while the sum is 72.

The spelling of 991759676544 in words is "nine hundred ninety-one billion, seven hundred fifty-nine million, six hundred seventy-six thousand, five hundred forty-four".