71664447 has 16 divisors (see below), whose sum is σ = 102235520. Its totient is φ = 44517600.

The previous prime is 71664443. The next prime is 71664451. The reversal of 71664447 is 74446617.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (71664443) and next prime (71664451).

It is not a de Polignac number, because 71664447 - 2² = 71664443 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 (71664443) 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 15 ways as a sum of consecutive naturals, for example, 6829 + ... + 13782.

It is an arithmetic number, because the mean of its divisors is an integer number (6389720).

Almost surely, 2^71664447 is an apocalyptic number.

71664447 is a deficient number, since it is larger than the sum of its proper divisors (30571073).

71664447 is a wasteful number, since it uses less digits than its factorization.

71664447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20694.

The product of its digits is 112896, while the sum is 39.

The square root of 71664447 is about 8465.4856328506. The cubic root of 71664447 is about 415.3694817558.

The spelling of 71664447 in words is "seventy-one million, six hundred sixty-four thousand, four hundred forty-seven".