991584166 has 16 divisors (see below), whose sum is σ = 1541219328. Its totient is φ = 477966600.

The previous prime is 991584157. The next prime is 991584169. The reversal of 991584166 is 661485199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991584169) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14100 + ... + 46711.

It is an arithmetic number, because the mean of its divisors is an integer number (96326208).

Almost surely, 2^991584166 is an apocalyptic number.

991584166 is a deficient number, since it is larger than the sum of its proper divisors (549635162).

991584166 is a wasteful number, since it uses less digits than its factorization.

991584166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61107.

The product of its digits is 466560, while the sum is 49.

The square root of 991584166 is about 31489.4294327477. The cubic root of 991584166 is about 997.1868154137.

The spelling of 991584166 in words is "nine hundred ninety-one million, five hundred eighty-four thousand, one hundred sixty-six".