81333904 has 20 divisors (see below), whose sum is σ = 158722480. Its totient is φ = 40373280.

The previous prime is 81333883. The next prime is 81333907. The reversal of 81333904 is 40933318.

It is not an unprimeable number, because it can be changed into a prime (81333907) 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 3 ways as a sum of consecutive naturals, for example, 16062 + ... + 20509.

It is an arithmetic number, because the mean of its divisors is an integer number (7936124).

Almost surely, 2^81333904 is an apocalyptic number.

It is an amenable number.

81333904 is a deficient number, since it is larger than the sum of its proper divisors (77388576).

81333904 is a wasteful number, since it uses less digits than its factorization.

81333904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36718 (or 36712 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 81333904 is about 9018.5311442607. The cubic root of 81333904 is about 433.2685904590.

The spelling of 81333904 in words is "eighty-one million, three hundred thirty-three thousand, nine hundred four".