71981613 has 48 divisors (see below), whose sum is σ = 119461056. Its totient is φ = 41368320.

The previous prime is 71981573. The next prime is 71981617. The reversal of 71981613 is 31618917.

It is not a de Polignac number, because 71981613 - 2¹⁶ = 71916077 is a prime.

It is a super-2 number, since 2×71981613² = 10362705220163538, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71981617) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 157281 + ... + 157737.

It is an arithmetic number, because the mean of its divisors is an integer number (2488772).

Almost surely, 2^71981613 is an apocalyptic number.

It is an amenable number.

71981613 is a deficient number, since it is larger than the sum of its proper divisors (47479443).

71981613 is a wasteful number, since it uses less digits than its factorization.

71981613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554 (or 551 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 71981613 is about 8484.1978406918. The cubic root of 71981613 is about 415.9813481683.

The spelling of 71981613 in words is "seventy-one million, nine hundred eighty-one thousand, six hundred thirteen".