81533373 has 4 divisors (see below), whose sum is σ = 108711168. Its totient is φ = 54355580.

The previous prime is 81533363. The next prime is 81533381. The reversal of 81533373 is 37333518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81533373 - 2⁴ = 81533357 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81533303) 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, 13588893 + ... + 13588898.

It is an arithmetic number, because the mean of its divisors is an integer number (27177792).

Almost surely, 2^81533373 is an apocalyptic number.

It is an amenable number.

81533373 is a deficient number, since it is larger than the sum of its proper divisors (27177795).

81533373 is a wasteful number, since it uses less digits than its factorization.

81533373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27177794.

The product of its digits is 22680, while the sum is 33.

The square root of 81533373 is about 9029.5832129728. The cubic root of 81533373 is about 433.6224941155.

The spelling of 81533373 in words is "eighty-one million, five hundred thirty-three thousand, three hundred seventy-three".