56720731 has 4 divisors (see below), whose sum is σ = 58550464. Its totient is φ = 54891000.

The previous prime is 56720711. The next prime is 56720743. The reversal of 56720731 is 13702765.

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 56720731 - 2²¹ = 54623579 is a prime.

It is a super-2 number, since 2×56720731² = 6434482650348722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 1829701 = 56720731 / (5 + 6 + 7 + 2 + 0 + 7 + 3 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 56720693 and 56720702.

It is not an unprimeable number, because it can be changed into a prime (56720701) 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, 914820 + ... + 914881.

It is an arithmetic number, because the mean of its divisors is an integer number (14637616).

Almost surely, 2^56720731 is an apocalyptic number.

56720731 is a deficient number, since it is larger than the sum of its proper divisors (1829733).

56720731 is a wasteful number, since it uses less digits than its factorization.

56720731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1829732.

The product of its (nonzero) digits is 8820, while the sum is 31.

The square root of 56720731 is about 7531.3166843521. The cubic root of 56720731 is about 384.2205651079.

The spelling of 56720731 in words is "fifty-six million, seven hundred twenty thousand, seven hundred thirty-one".