991134737680 has 40 divisors (see below), whose sum is σ = 2383849935000. Its totient is φ = 382783070208.

The previous prime is 991134737669. The next prime is 991134737701. The reversal of 991134737680 is 86737431199.

It can be written as a sum of positive squares in 4 ways, for example, as 330965487616 + 660169250064 = 575296^2 + 812508^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (58).

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 213604305 + ... + 213608944.

It is an arithmetic number, because the mean of its divisors is an integer number (59596248375).

Almost surely, 2^991134737680 is an apocalyptic number.

It is an amenable number.

991134737680 is an abundant number, since it is smaller than the sum of its proper divisors (1392715197320).

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

991134737680 is a wasteful number, since it uses less digits than its factorization.

991134737680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427213291 (or 427213285 counting only the distinct ones).

The product of its (nonzero) digits is 6858432, while the sum is 58.

The spelling of 991134737680 in words is "nine hundred ninety-one billion, one hundred thirty-four million, seven hundred thirty-seven thousand, six hundred eighty".