71731391 has 2 divisors, whose sum is σ = 71731392. Its totient is φ = 71731390.

The previous prime is 71731379. The next prime is 71731417. The reversal of 71731391 is 19313717.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71731391 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71731351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35865695 + 35865696.

It is an arithmetic number, because the mean of its divisors is an integer number (35865696).

Almost surely, 2^71731391 is an apocalyptic number.

71731391 is a deficient number, since it is larger than the sum of its proper divisors (1).

71731391 is an equidigital number, since it uses as much as digits as its factorization.

71731391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3969, while the sum is 32.

The square root of 71731391 is about 8469.4386472776. The cubic root of 71731391 is about 415.4987780430.

The spelling of 71731391 in words is "seventy-one million, seven hundred thirty-one thousand, three hundred ninety-one".