71685391 has 4 divisors (see below), whose sum is σ = 73622872. Its totient is φ = 69747912.

The previous prime is 71685371. The next prime is 71685407. The reversal of 71685391 is 19358617.

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 71685391 - 2⁵ = 71685359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71685301) 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 in 3 ways as a sum of consecutive naturals, for example, 968685 + ... + 968758.

It is an arithmetic number, because the mean of its divisors is an integer number (18405718).

Almost surely, 2^71685391 is an apocalyptic number.

71685391 is a deficient number, since it is larger than the sum of its proper divisors (1937481).

71685391 is a wasteful number, since it uses less digits than its factorization.

71685391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1937480.

The product of its digits is 45360, while the sum is 40.

The square root of 71685391 is about 8466.7225654323. The cubic root of 71685391 is about 415.4099418512.

The spelling of 71685391 in words is "seventy-one million, six hundred eighty-five thousand, three hundred ninety-one".