1991316968 has 16 divisors (see below), whose sum is σ = 3739244580. Its totient is φ = 994185088.

The previous prime is 1991316959. The next prime is 1991316979. The reversal of 1991316968 is 8696131991.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1544332804 + 446984164 = 39298^2 + 21142^2 .

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, 178421 + ... + 189252.

Almost surely, 2^1991316968 is an apocalyptic number.

It is an amenable number.

1991316968 is a deficient number, since it is larger than the sum of its proper divisors (1747927612).

1991316968 is a wasteful number, since it uses less digits than its factorization.

1991316968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368356 (or 368352 counting only the distinct ones).

The product of its digits is 629856, while the sum is 53.

The square root of 1991316968 is about 44624.1747038531. The cubic root of 1991316968 is about 1258.0950823852.

The spelling of 1991316968 in words is "one billion, nine hundred ninety-one million, three hundred sixteen thousand, nine hundred sixty-eight".