71981569 has 6 divisors (see below), whose sum is σ = 79120370. Its totient is φ = 65437680.

The previous prime is 71981563. The next prime is 71981573. The reversal of 71981569 is 96518917.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 65011969 + 6969600 = 8063^2 + 2640^2 .

It is not a de Polignac number, because 71981569 - 2⁵ = 71981537 is a prime.

It is a super-2 number, since 2×71981569² = 10362692551403522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71981563) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 297324 + ... + 297565.

Almost surely, 2^71981569 is an apocalyptic number.

It is an amenable number.

71981569 is a deficient number, since it is larger than the sum of its proper divisors (7138801).

71981569 is a wasteful number, since it uses less digits than its factorization.

71981569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594911 (or 594900 counting only the distinct ones).

The product of its digits is 136080, while the sum is 46.

The square root of 71981569 is about 8484.1952476355. The cubic root of 71981569 is about 415.9812634097.

The spelling of 71981569 in words is "seventy-one million, nine hundred eighty-one thousand, five hundred sixty-nine".