81391696 has 20 divisors (see below), whose sum is σ = 158051392. Its totient is φ = 40604256.

The previous prime is 81391693. The next prime is 81391703. The reversal of 81391696 is 69619318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81391693) 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, 1915 + ... + 12901.

Almost surely, 2^81391696 is an apocalyptic number.

It is an amenable number.

81391696 is a deficient number, since it is larger than the sum of its proper divisors (76659696).

81391696 is a wasteful number, since it uses less digits than its factorization.

81391696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11458 (or 11452 counting only the distinct ones).

The product of its digits is 69984, while the sum is 43.

The square root of 81391696 is about 9021.7346447343. The cubic root of 81391696 is about 433.3711861740.

The spelling of 81391696 in words is "eighty-one million, three hundred ninety-one thousand, six hundred ninety-six".