1991750664 has 64 divisors (see below), whose sum is σ = 5054212800. Its totient is φ = 654004224.

The previous prime is 1991750641. The next prime is 1991750689. The reversal of 1991750664 is 4660571991.

It is a happy number.

1991750664 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 526572 + ... + 530340.

It is an arithmetic number, because the mean of its divisors is an integer number (78972075).

Almost surely, 2^1991750664 is an apocalyptic number.

It is an amenable number.

1991750664 is an abundant number, since it is smaller than the sum of its proper divisors (3062462136).

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

1991750664 is a wasteful number, since it uses less digits than its factorization.

1991750664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4102 (or 4098 counting only the distinct ones).

The product of its (nonzero) digits is 408240, while the sum is 48.

The square root of 1991750664 is about 44629.0338680998. The cubic root of 1991750664 is about 1258.1864107551.

The spelling of 1991750664 in words is "one billion, nine hundred ninety-one million, seven hundred fifty thousand, six hundred sixty-four".