71664839 has 4 divisors (see below), whose sum is σ = 73976640. Its totient is φ = 69353040.

The previous prime is 71664821. The next prime is 71664907. The reversal of 71664839 is 93846617.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93846617 = 3251 ⋅28867.

It is a cyclic number.

It is not a de Polignac number, because 71664839 - 2⁸ = 71664583 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 71664839.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71664239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1155854 + ... + 1155915.

It is an arithmetic number, because the mean of its divisors is an integer number (18494160).

Almost surely, 2^71664839 is an apocalyptic number.

71664839 is a deficient number, since it is larger than the sum of its proper divisors (2311801).

71664839 is a wasteful number, since it uses less digits than its factorization.

71664839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2311800.

The product of its digits is 217728, while the sum is 44.

The square root of 71664839 is about 8465.5087856549. The cubic root of 71664839 is about 415.3702391027.

The spelling of 71664839 in words is "seventy-one million, six hundred sixty-four thousand, eight hundred thirty-nine".