81664293 has 8 divisors (see below), whose sum is σ = 108934848. Its totient is φ = 54418304.

The previous prime is 81664259. The next prime is 81664321. The reversal of 81664293 is 39246618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81664293 - 2¹³ = 81656101 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81666293) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4021 + ... + 13397.

It is an arithmetic number, because the mean of its divisors is an integer number (13616856).

Almost surely, 2^81664293 is an apocalyptic number.

It is an amenable number.

81664293 is a deficient number, since it is larger than the sum of its proper divisors (27270555).

81664293 is a wasteful number, since it uses less digits than its factorization.

81664293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12283.

The product of its digits is 62208, while the sum is 39.

The square root of 81664293 is about 9036.8298091753. The cubic root of 81664293 is about 433.8544625164.

The spelling of 81664293 in words is "eighty-one million, six hundred sixty-four thousand, two hundred ninety-three".