81693331 has 8 divisors (see below), whose sum is σ = 87030720. Its totient is φ = 76459752.

The previous prime is 81693289. The next prime is 81693371. The reversal of 81693331 is 13339618.

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 81693331 - 2¹¹ = 81691283 is a prime.

It is a super-2 number, since 2×81693331² = 13347600659751122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81693371) 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, 24325 + ... + 27478.

It is an arithmetic number, because the mean of its divisors is an integer number (10878840).

Almost surely, 2^81693331 is an apocalyptic number.

81693331 is a deficient number, since it is larger than the sum of its proper divisors (5337389).

81693331 is a wasteful number, since it uses less digits than its factorization.

81693331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51905.

The product of its digits is 11664, while the sum is 34.

The square root of 81693331 is about 9038.4363138764. The cubic root of 81693331 is about 433.9058794107.

The spelling of 81693331 in words is "eighty-one million, six hundred ninety-three thousand, three hundred thirty-one".