991309938 has 8 divisors (see below), whose sum is σ = 1982619888. Its totient is φ = 330436644.

The previous prime is 991309903. The next prime is 991309961. The reversal of 991309938 is 839903199.

It is a sphenic number, since it is the product of 3 distinct primes.

991309938 is an admirable 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, 82609156 + ... + 82609167.

It is an arithmetic number, because the mean of its divisors is an integer number (247827486).

Almost surely, 2^991309938 is an apocalyptic number.

991309938 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991309938 is a wasteful number, since it uses less digits than its factorization.

991309938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165218328.

The product of its (nonzero) digits is 472392, while the sum is 51.

The square root of 991309938 is about 31485.0748450754. The cubic root of 991309938 is about 997.0948811238.

The spelling of 991309938 in words is "nine hundred ninety-one million, three hundred nine thousand, nine hundred thirty-eight".