991166128 has 10 divisors (see below), whose sum is σ = 1920384404. Its totient is φ = 495583056.

The previous prime is 991166123. The next prime is 991166129. The reversal of 991166128 is 821661199.

It is not an unprimeable number, because it can be changed into a prime (991166123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30973926 + ... + 30973957.

Almost surely, 2^991166128 is an apocalyptic number.

It is an amenable number.

991166128 is a deficient number, since it is larger than the sum of its proper divisors (929218276).

991166128 is a wasteful number, since it uses less digits than its factorization.

991166128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61947891 (or 61947885 counting only the distinct ones).

The product of its digits is 46656, while the sum is 43.

The square root of 991166128 is about 31482.7909817411. The cubic root of 991166128 is about 997.0466623835.

The spelling of 991166128 in words is "nine hundred ninety-one million, one hundred sixty-six thousand, one hundred twenty-eight".