1991278912 has 112 divisors (see below), whose sum is σ = 4747564800. Its totient is φ = 810196992.

The previous prime is 1991278909. The next prime is 1991278963. The reversal of 1991278912 is 2198721991.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (112).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1534648 + ... + 1535944.

Almost surely, 2^1991278912 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991278912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2373782400).

1991278912 is an abundant number, since it is smaller than the sum of its proper divisors (2756285888).

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

1991278912 is a wasteful number, since it uses less digits than its factorization.

1991278912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1488 (or 1478 counting only the distinct ones).

The product of its digits is 163296, while the sum is 49.

The square root of 1991278912 is about 44623.7482961707. The cubic root of 1991278912 is about 1258.0870678615.

The spelling of 1991278912 in words is "one billion, nine hundred ninety-one million, two hundred seventy-eight thousand, nine hundred twelve".