71856731 has 4 divisors (see below), whose sum is σ = 72664200. Its totient is φ = 71049264.

The previous prime is 71856713. The next prime is 71856737. The reversal of 71856731 is 13765817.

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 71856731 - 2¹⁸ = 71594587 is a prime.

It is a super-2 number, since 2×71856731² = 10326779580012722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71856737) 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, 403601 + ... + 403778.

It is an arithmetic number, because the mean of its divisors is an integer number (18166050).

Almost surely, 2^71856731 is an apocalyptic number.

71856731 is a deficient number, since it is larger than the sum of its proper divisors (807469).

71856731 is an equidigital number, since it uses as much as digits as its factorization.

71856731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 807468.

The product of its digits is 35280, while the sum is 38.

The square root of 71856731 is about 8476.8349635934. The cubic root of 71856731 is about 415.7406447827.

The spelling of 71856731 in words is "seventy-one million, eight hundred fifty-six thousand, seven hundred thirty-one".