81731694 has 32 divisors (see below), whose sum is σ = 179199360. Its totient is φ = 24645600.

The previous prime is 81731687. The next prime is 81731701. The reversal of 81731694 is 49613718.

It is an interprime number because it is at equal distance from previous prime (81731687) and next prime (81731701).

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10992 + ... + 16860.

It is an arithmetic number, because the mean of its divisors is an integer number (5599980).

Almost surely, 2^81731694 is an apocalyptic number.

81731694 is an abundant number, since it is smaller than the sum of its proper divisors (97467666).

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

81731694 is a wasteful number, since it uses less digits than its factorization.

81731694 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6096.

The product of its digits is 36288, while the sum is 39.

The square root of 81731694 is about 9040.5582792215. The cubic root of 81731694 is about 433.9737891821.

The spelling of 81731694 in words is "eighty-one million, seven hundred thirty-one thousand, six hundred ninety-four".