1991456339 has 4 divisors (see below), whose sum is σ = 1999390680. Its totient is φ = 1983522000.

The previous prime is 1991456309. The next prime is 1991456417. The reversal of 1991456339 is 9336541991.

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

It is a cyclic number.

It is not a de Polignac number, because 1991456339 - 2²⁴ = 1974679123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1991456309) 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, 3966794 + ... + 3967295.

It is an arithmetic number, because the mean of its divisors is an integer number (499847670).

Almost surely, 2^1991456339 is an apocalyptic number.

1991456339 is a deficient number, since it is larger than the sum of its proper divisors (7934341).

1991456339 is an equidigital number, since it uses as much as digits as its factorization.

1991456339 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7934340.

The product of its digits is 787320, while the sum is 50.

The square root of 1991456339 is about 44625.7362852424. The cubic root of 1991456339 is about 1258.1244327903.

The spelling of 1991456339 in words is "one billion, nine hundred ninety-one million, four hundred fifty-six thousand, three hundred thirty-nine".