81211333 has 4 divisors (see below), whose sum is σ = 92812960. Its totient is φ = 69609708.

The previous prime is 81211309. The next prime is 81211349. The reversal of 81211333 is 33311218.

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 not a de Polignac number, because 81211333 - 2²⁵ = 47656901 is a prime.

It is a Duffinian number.

It is a zygodrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81211393) 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, 5800803 + ... + 5800816.

It is an arithmetic number, because the mean of its divisors is an integer number (23203240).

Almost surely, 2^81211333 is an apocalyptic number.

It is an amenable number.

81211333 is a deficient number, since it is larger than the sum of its proper divisors (11601627).

81211333 is a wasteful number, since it uses less digits than its factorization.

81211333 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11601626.

The product of its digits is 432, while the sum is 22.

The square root of 81211333 is about 9011.7330741650. The cubic root of 81211333 is about 433.0508343478.

The spelling of 81211333 in words is "eighty-one million, two hundred eleven thousand, three hundred thirty-three".