81694817 has 4 divisors (see below), whose sum is σ = 81739056. Its totient is φ = 81650580.

The previous prime is 81694807. The next prime is 81694829. The reversal of 81694817 is 71849618.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81694817 - 2¹⁶ = 81629281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81694807) 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, 19223 + ... + 23084.

It is an arithmetic number, because the mean of its divisors is an integer number (20434764).

Almost surely, 2^81694817 is an apocalyptic number.

It is an amenable number.

81694817 is a deficient number, since it is larger than the sum of its proper divisors (44239).

81694817 is a wasteful number, since it uses less digits than its factorization.

81694817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44238.

The product of its digits is 96768, while the sum is 44.

The square root of 81694817 is about 9038.5185179873. The cubic root of 81694817 is about 433.9085103077.

The spelling of 81694817 in words is "eighty-one million, six hundred ninety-four thousand, eight hundred seventeen".