81664443233 has 8 divisors (see below), whose sum is σ = 81989314176. Its totient is φ = 81339681600.

The previous prime is 81664443227. The next prime is 81664443253. The reversal of 81664443233 is 33234446618.

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 81664443233 - 2⁶ = 81664443169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81664443253) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1680548 + ... + 1728458.

It is an arithmetic number, because the mean of its divisors is an integer number (10248664272).

Almost surely, 2^81664443233 is an apocalyptic number.

It is an amenable number.

81664443233 is a deficient number, since it is larger than the sum of its proper divisors (324870943).

81664443233 is a wasteful number, since it uses less digits than its factorization.

81664443233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54655.

The product of its digits is 995328, while the sum is 44.

The spelling of 81664443233 in words is "eighty-one billion, six hundred sixty-four million, four hundred forty-three thousand, two hundred thirty-three".