991259912 has 8 divisors (see below), whose sum is σ = 1858612350. Its totient is φ = 495629952.

The previous prime is 991259861. The next prime is 991259921. The reversal of 991259912 is 219952199.

It can be written as a sum of positive squares in only one way, i.e., 717489796 + 273770116 = 26786^2 + 16546^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61953737 + ... + 61953752.

Almost surely, 2^991259912 is an apocalyptic number.

It is an amenable number.

991259912 is a deficient number, since it is larger than the sum of its proper divisors (867352438).

991259912 is a wasteful number, since it uses less digits than its factorization.

991259912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123907495 (or 123907491 counting only the distinct ones).

The product of its digits is 131220, while the sum is 47.

The square root of 991259912 is about 31484.2803951432. The cubic root of 991259912 is about 997.0781081968.

The spelling of 991259912 in words is "nine hundred ninety-one million, two hundred fifty-nine thousand, nine hundred twelve".