991173364580 has 48 divisors (see below), whose sum is σ = 2400640112640. Its totient is φ = 336713148288.

The previous prime is 991173364499. The next prime is 991173364589. The reversal of 991173364580 is 85463371199.

It is not an unprimeable number, because it can be changed into a prime (991173364589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32460932 + ... + 32491451.

It is an arithmetic number, because the mean of its divisors is an integer number (50013335680).

Almost surely, 2^991173364580 is an apocalyptic number.

It is an amenable number.

991173364580 is an abundant number, since it is smaller than the sum of its proper divisors (1409466748060).

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

991173364580 is a wasteful number, since it uses less digits than its factorization.

991173364580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64952508 (or 64952506 counting only the distinct ones).

The product of its (nonzero) digits is 4898880, while the sum is 56.

The spelling of 991173364580 in words is "nine hundred ninety-one billion, one hundred seventy-three million, three hundred sixty-four thousand, five hundred eighty".