991439912 has 32 divisors (see below), whose sum is σ = 1958779200. Its totient is φ = 469152000.

The previous prime is 991439899. The next prime is 991439921. The reversal of 991439912 is 219934199.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 179837 + ... + 185267.

It is an arithmetic number, because the mean of its divisors is an integer number (61211850).

Almost surely, 2^991439912 is an apocalyptic number.

It is an amenable number.

991439912 is a deficient number, since it is larger than the sum of its proper divisors (967339288).

991439912 is a wasteful number, since it uses less digits than its factorization.

991439912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6657 (or 6653 counting only the distinct ones).

The product of its digits is 157464, while the sum is 47.

The square root of 991439912 is about 31487.1388347687. The cubic root of 991439912 is about 997.1384567139.

The spelling of 991439912 in words is "nine hundred ninety-one million, four hundred thirty-nine thousand, nine hundred twelve".