81133308 has 18 divisors (see below), whose sum is σ = 205087064. Its totient is φ = 27044424.

The previous prime is 81133289. The next prime is 81133309. The reversal of 81133308 is 80333118.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×81133308² = 13165227334045728, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81133309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1126816 + ... + 1126887.

Almost surely, 2^81133308 is an apocalyptic number.

It is an amenable number.

81133308 is an abundant number, since it is smaller than the sum of its proper divisors (123953756).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81133308 is a wasteful number, since it uses less digits than its factorization.

81133308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2253713 (or 2253708 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 81133308 is about 9007.4029553473. The cubic root of 81133308 is about 432.9121032253.

The spelling of 81133308 in words is "eighty-one million, one hundred thirty-three thousand, three hundred eight".