56381581 has 4 divisors (see below), whose sum is σ = 56396700. Its totient is φ = 56366464.

The previous prime is 56381551. The next prime is 56381587. The reversal of 56381581 is 18518365.

56381581 = 5309² + 5310².

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18518365 = 5 ⋅3703673.

It can be written as a sum of positive squares in 2 ways, for example, as 28196100 + 28185481 = 5310^2 + 5309^2 .

It is a cyclic number.

It is not a de Polignac number, because 56381581 - 2¹³ = 56373389 is a prime.

It is a super-2 number, since 2×56381581² = 6357765352119122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 56381581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56381587) 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, 2475 + ... + 10903.

It is an arithmetic number, because the mean of its divisors is an integer number (14099175).

Almost surely, 2^56381581 is an apocalyptic number.

56381581 is the 5310-th centered square number.

It is an amenable number.

56381581 is a deficient number, since it is larger than the sum of its proper divisors (15119).

56381581 is an equidigital number, since it uses as much as digits as its factorization.

56381581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15118.

The product of its digits is 28800, while the sum is 37.

The square root of 56381581 is about 7508.7669427144. The cubic root of 56381581 is about 383.4532443181.

The spelling of 56381581 in words is "fifty-six million, three hundred eighty-one thousand, five hundred eighty-one".