81586616 has 16 divisors (see below), whose sum is σ = 155568600. Its totient is φ = 40101664.

The previous prime is 81586613. The next prime is 81586639. The reversal of 81586616 is 61668518.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81586613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85955 + ... + 86898.

Almost surely, 2^81586616 is an apocalyptic number.

It is an amenable number.

81586616 is a deficient number, since it is larger than the sum of its proper divisors (73981984).

81586616 is a wasteful number, since it uses less digits than its factorization.

81586616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172918 (or 172914 counting only the distinct ones).

The product of its digits is 69120, while the sum is 41.

The square root of 81586616 is about 9032.5309852776. The cubic root of 81586616 is about 433.7168617670.

The spelling of 81586616 in words is "eighty-one million, five hundred eighty-six thousand, six hundred sixteen".