991687148 has 12 divisors (see below), whose sum is σ = 1791435072. Its totient is φ = 479848560.

The previous prime is 991687141. The next prime is 991687157. The reversal of 991687148 is 841786199.

It is a self number, because there is not a number n which added to its sum of digits gives 991687148.

It is not an unprimeable number, because it can be changed into a prime (991687141) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3998615 + ... + 3998862.

It is an arithmetic number, because the mean of its divisors is an integer number (149286256).

Almost surely, 2^991687148 is an apocalyptic number.

It is an amenable number.

991687148 is a deficient number, since it is larger than the sum of its proper divisors (799747924).

991687148 is a wasteful number, since it uses less digits than its factorization.

991687148 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7997512 (or 7997510 counting only the distinct ones).

The product of its digits is 870912, while the sum is 53.

The square root of 991687148 is about 31491.0645739391. The cubic root of 991687148 is about 997.2213355083.

The spelling of 991687148 in words is "nine hundred ninety-one million, six hundred eighty-seven thousand, one hundred forty-eight".