1991953256 has 16 divisors (see below), whose sum is σ = 3771175200. Its totient is φ = 986306544.

The previous prime is 1991953253. The next prime is 1991953273. The reversal of 1991953256 is 6523591991.

It is not an unprimeable number, because it can be changed into a prime (1991953253) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1207886 + ... + 1209533.

It is an arithmetic number, because the mean of its divisors is an integer number (235698450).

Almost surely, 2^1991953256 is an apocalyptic number.

It is an amenable number.

1991953256 is a deficient number, since it is larger than the sum of its proper divisors (1779221944).

1991953256 is a wasteful number, since it uses less digits than its factorization.

1991953256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2417528 (or 2417524 counting only the distinct ones).

The product of its digits is 656100, while the sum is 50.

The square root of 1991953256 is about 44631.3035435892. The cubic root of 1991953256 is about 1258.2290683468.

The spelling of 1991953256 in words is "one billion, nine hundred ninety-one million, nine hundred fifty-three thousand, two hundred fifty-six".