991806164 has 12 divisors (see below), whose sum is σ = 1782570804. Its totient is φ = 482500224.

The previous prime is 991806149. The next prime is 991806191. The reversal of 991806164 is 461608199.

It can be written as a sum of positive squares in 2 ways, for example, as 751308100 + 240498064 = 27410^2 + 15508^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3350549 + ... + 3350844.

It is an arithmetic number, because the mean of its divisors is an integer number (148547567).

Almost surely, 2^991806164 is an apocalyptic number.

It is an amenable number.

991806164 is a deficient number, since it is larger than the sum of its proper divisors (790764640).

991806164 is a wasteful number, since it uses less digits than its factorization.

991806164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6701434 (or 6701432 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 991806164 is about 31492.9541961373. The cubic root of 991806164 is about 997.2612273052.

The spelling of 991806164 in words is "nine hundred ninety-one million, eight hundred six thousand, one hundred sixty-four".