56031781 has 6 divisors (see below), whose sum is σ = 60673650. Its totient is φ = 51721488.

The previous prime is 56031763. The next prime is 56031791. The reversal of 56031781 is 18713065.

It can be written as a sum of positive squares in 3 ways, for example, as 1876900 + 54154881 = 1370^2 + 7359^2 .

It is a de Polignac number, because none of the positive numbers 2^k-56031781 is a prime.

It is a super-2 number, since 2×56031781² = 6279120964063922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56031761) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 165606 + ... + 165943.

It is an arithmetic number, because the mean of its divisors is an integer number (10112275).

Almost surely, 2^56031781 is an apocalyptic number.

It is an amenable number.

56031781 is a deficient number, since it is larger than the sum of its proper divisors (4641869).

56031781 is a wasteful number, since it uses less digits than its factorization.

56031781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331575 (or 331562 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 56031781 is about 7485.4379297407. The cubic root of 56031781 is about 382.6585977078.

The spelling of 56031781 in words is "fifty-six million, thirty-one thousand, seven hundred eighty-one".