1991335393 has 4 divisors (see below), whose sum is σ = 2002337428. Its totient is φ = 1980333360.

The previous prime is 1991335387. The next prime is 1991335399. The reversal of 1991335393 is 3935331991.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1991335387) and next prime (1991335399).

It can be written as a sum of positive squares in 2 ways, for example, as 405941904 + 1585393489 = 20148^2 + 39817^2 .

It is a cyclic number.

It is not a de Polignac number, because 1991335393 - 2⁵ = 1991335361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1991335399) 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, 5500746 + ... + 5501107.

It is an arithmetic number, because the mean of its divisors is an integer number (500584357).

Almost surely, 2^1991335393 is an apocalyptic number.

It is an amenable number.

1991335393 is a deficient number, since it is larger than the sum of its proper divisors (11002035).

1991335393 is a wasteful number, since it uses less digits than its factorization.

1991335393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11002034.

The product of its digits is 295245, while the sum is 46.

The square root of 1991335393 is about 44624.3811497706. The cubic root of 1991335393 is about 1258.0989626197.

The spelling of 1991335393 in words is "one billion, nine hundred ninety-one million, three hundred thirty-five thousand, three hundred ninety-three".