81338533 has 8 divisors (see below), whose sum is σ = 84268800. Its totient is φ = 78416688.

The previous prime is 81338527. The next prime is 81338539. The reversal of 81338533 is 33583318.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81338527) and next prime (81338539).

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 81338533 - 2⁵ = 81338501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81338539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22660 + ... + 26002.

It is an arithmetic number, because the mean of its divisors is an integer number (10533600).

Almost surely, 2^81338533 is an apocalyptic number.

It is an amenable number.

81338533 is a deficient number, since it is larger than the sum of its proper divisors (2930267).

81338533 is a wasteful number, since it uses less digits than its factorization.

81338533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4211.

The product of its digits is 25920, while the sum is 34.

The square root of 81338533 is about 9018.7877788537. The cubic root of 81338533 is about 433.2768099187.

The spelling of 81338533 in words is "eighty-one million, three hundred thirty-eight thousand, five hundred thirty-three".