56783991 has 16 divisors (see below), whose sum is σ = 83064960. Its totient is φ = 34218720.

The previous prime is 56783983. The next prime is 56784023. The reversal of 56783991 is 19938765.

It is not a de Polignac number, because 56783991 - 2³ = 56783983 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 56783991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56783921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1101 + ... + 10713.

It is an arithmetic number, because the mean of its divisors is an integer number (5191560).

Almost surely, 2^56783991 is an apocalyptic number.

56783991 is a deficient number, since it is larger than the sum of its proper divisors (26280969).

56783991 is a wasteful number, since it uses less digits than its factorization.

56783991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9806.

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

The square root of 56783991 is about 7535.5153108464. The cubic root of 56783991 is about 384.3633510119.

It can be divided in two parts, 5678 and 3991, that added together give a palindrome (9669).

The spelling of 56783991 in words is "fifty-six million, seven hundred eighty-three thousand, nine hundred ninety-one".