71688731 has 2 divisors, whose sum is σ = 71688732. Its totient is φ = 71688730.

The previous prime is 71688649. The next prime is 71688733. The reversal of 71688731 is 13788617.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71688731 is a prime.

It is a super-2 number, since 2×71688731² = 10278548304780722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 71688733, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (71688733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35844365 + 35844366.

It is an arithmetic number, because the mean of its divisors is an integer number (35844366).

Almost surely, 2^71688731 is an apocalyptic number.

71688731 is a deficient number, since it is larger than the sum of its proper divisors (1).

71688731 is an equidigital number, since it uses as much as digits as its factorization.

71688731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56448, while the sum is 41.

The square root of 71688731 is about 8466.9198059271. The cubic root of 71688731 is about 415.4163934105.

The spelling of 71688731 in words is "seventy-one million, six hundred eighty-eight thousand, seven hundred thirty-one".