71981656 has 16 divisors (see below), whose sum is σ = 138105000. Its totient is φ = 35153664.

The previous prime is 71981617. The next prime is 71981677. The reversal of 71981656 is 65618917.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (43).

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 3 ways as a sum of consecutive naturals, for example, 104281 + ... + 104968.

Almost surely, 2^71981656 is an apocalyptic number.

It is an amenable number.

71981656 is a deficient number, since it is larger than the sum of its proper divisors (66123344).

71981656 is a wasteful number, since it uses less digits than its factorization.

71981656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209298 (or 209294 counting only the distinct ones).

The product of its digits is 90720, while the sum is 43.

The square root of 71981656 is about 8484.2003748144. The cubic root of 71981656 is about 415.9814310005.

The spelling of 71981656 in words is "seventy-one million, nine hundred eighty-one thousand, six hundred fifty-six".