56213781 has 16 divisors (see below), whose sum is σ = 85466304. Its totient is φ = 32557824.

The previous prime is 56213749. The next prime is 56213791. The reversal of 56213781 is 18731265.

It is not a de Polignac number, because 56213781 - 2⁵ = 56213749 is a prime.

It is a super-2 number, since 2×56213781² = 6319978348631922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56213701) 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, 41731 + ... + 43056.

It is an arithmetic number, because the mean of its divisors is an integer number (5341644).

Almost surely, 2^56213781 is an apocalyptic number.

56213781 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

56213781 is a deficient number, since it is larger than the sum of its proper divisors (29252523).

56213781 is a wasteful number, since it uses less digits than its factorization.

56213781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84820.

The product of its digits is 10080, while the sum is 33.

The square root of 56213781 is about 7497.5850111886. The cubic root of 56213781 is about 383.0724616174.

The spelling of 56213781 in words is "fifty-six million, two hundred thirteen thousand, seven hundred eighty-one".