81333293 has 4 divisors (see below), whose sum is σ = 82079580. Its totient is φ = 80587008.

The previous prime is 81333283. The next prime is 81333311. The reversal of 81333293 is 39233318.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 25786084 + 55547209 = 5078^2 + 7453^2 .

It is a cyclic number.

It is not a de Polignac number, because 81333293 - 2¹² = 81329197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81333233) 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, 372980 + ... + 373197.

It is an arithmetic number, because the mean of its divisors is an integer number (20519895).

Almost surely, 2^81333293 is an apocalyptic number.

It is an amenable number.

81333293 is a deficient number, since it is larger than the sum of its proper divisors (746287).

81333293 is a wasteful number, since it uses less digits than its factorization.

81333293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 746286.

The product of its digits is 11664, while the sum is 32.

The square root of 81333293 is about 9018.4972695012. The cubic root of 81333293 is about 433.2675055167.

The spelling of 81333293 in words is "eighty-one million, three hundred thirty-three thousand, two hundred ninety-three".