1991283264 has 140 divisors (see below), whose sum is σ = 6093691648. Its totient is φ = 642297600.

The previous prime is 1991283251. The next prime is 1991283293. The reversal of 1991283264 is 4623821991.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 154509 + ... + 166899.

Almost surely, 2^1991283264 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 1991283264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3046845824).

1991283264 is an abundant number, since it is smaller than the sum of its proper divisors (4102408384).

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

1991283264 is a wasteful number, since it uses less digits than its factorization.

1991283264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12446 (or 12427 counting only the distinct ones).

The product of its digits is 186624, while the sum is 45.

The square root of 1991283264 is about 44623.7970594166. The cubic root of 1991283264 is about 1258.0879843899.

The spelling of 1991283264 in words is "one billion, nine hundred ninety-one million, two hundred eighty-three thousand, two hundred sixty-four".