56717781 has 16 divisors (see below), whose sum is σ = 77895744. Its totient is φ = 36681984.

The previous prime is 56717779. The next prime is 56717789. The reversal of 56717781 is 18771765.

It is not a de Polignac number, because 56717781 - 2¹ = 56717779 is a prime.

It is a super-2 number, since 2×56717781² = 6433813363127922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56717789) 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, 57565 + ... + 58541.

It is an arithmetic number, because the mean of its divisors is an integer number (4868484).

Almost surely, 2^56717781 is an apocalyptic number.

It is an amenable number.

56717781 is a deficient number, since it is larger than the sum of its proper divisors (21177963).

56717781 is a wasteful number, since it uses less digits than its factorization.

56717781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1540.

The product of its digits is 82320, while the sum is 42.

The square root of 56717781 is about 7531.1208329172. The cubic root of 56717781 is about 384.2139039907.

The spelling of 56717781 in words is "fifty-six million, seven hundred seventeen thousand, seven hundred eighty-one".