991975843 has 12 divisors (see below), whose sum is σ = 1023706080. Its totient is φ = 960792800.

The previous prime is 991975837. The next prime is 991975847. The reversal of 991975843 is 348579199.

It is not a de Polignac number, because 991975843 - 2²⁵ = 958421411 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991975847) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 478413 + ... + 480481.

It is an arithmetic number, because the mean of its divisors is an integer number (85308840).

Almost surely, 2^991975843 is an apocalyptic number.

991975843 is a deficient number, since it is larger than the sum of its proper divisors (31730237).

991975843 is a wasteful number, since it uses less digits than its factorization.

991975843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2318 (or 2217 counting only the distinct ones).

The product of its digits is 2449440, while the sum is 55.

The square root of 991975843 is about 31495.6480009540. The cubic root of 991975843 is about 997.3180948145.

The spelling of 991975843 in words is "nine hundred ninety-one million, nine hundred seventy-five thousand, eight hundred forty-three".