71561664 has 56 divisors (see below), whose sum is σ = 210383120. Its totient is φ = 23853312.

The previous prime is 71561641. The next prime is 71561741. The reversal of 71561664 is 46616517.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 18979 + ... + 22434.

Almost surely, 2^71561664 is an apocalyptic number.

It is an amenable number.

71561664 is an abundant number, since it is smaller than the sum of its proper divisors (138821456).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

71561664 is a wasteful number, since it uses less digits than its factorization.

71561664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41434 (or 41418 counting only the distinct ones).

The product of its digits is 30240, while the sum is 36.

The square root of 71561664 is about 8459.4127455752. The cubic root of 71561664 is about 415.1708088669.

The spelling of 71561664 in words is "seventy-one million, five hundred sixty-one thousand, six hundred sixty-four".