81694336 has 32 divisors (see below), whose sum is σ = 163159200. Its totient is φ = 40744704.

The previous prime is 81694307. The next prime is 81694339. The reversal of 81694336 is 63349618.

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (81694339) 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, 94675 + ... + 95533.

It is an arithmetic number, because the mean of its divisors is an integer number (5098725).

Almost surely, 2^81694336 is an apocalyptic number.

It is an amenable number.

81694336 is a deficient number, since it is larger than the sum of its proper divisors (81464864).

81694336 is an equidigital number, since it uses as much as digits as its factorization.

81694336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1616 (or 1604 counting only the distinct ones).

The product of its digits is 93312, while the sum is 40.

The square root of 81694336 is about 9038.4919096053. The cubic root of 81694336 is about 433.9076587220.

The spelling of 81694336 in words is "eighty-one million, six hundred ninety-four thousand, three hundred thirty-six".