81130933 has 4 divisors (see below), whose sum is σ = 87371788. Its totient is φ = 74890080.

The previous prime is 81130921. The next prime is 81130939. The reversal of 81130933 is 33903118.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 33903118 = 2 ⋅16951559.

It can be written as a sum of positive squares in 2 ways, for example, as 23020804 + 58110129 = 4798^2 + 7623^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81130933 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 (81130939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3120408 + ... + 3120433.

It is an arithmetic number, because the mean of its divisors is an integer number (21842947).

Almost surely, 2^81130933 is an apocalyptic number.

It is an amenable number.

81130933 is a deficient number, since it is larger than the sum of its proper divisors (6240855).

81130933 is a wasteful number, since it uses less digits than its factorization.

81130933 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6240854.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 81130933 is about 9007.2711183799. The cubic root of 81130933 is about 432.9078789993.

The spelling of 81130933 in words is "eighty-one million, one hundred thirty thousand, nine hundred thirty-three".