81751833 has 12 divisors (see below), whose sum is σ = 121277988. Its totient is φ = 53028000.

The previous prime is 81751829. The next prime is 81751837. The reversal of 81751833 is 33815718.

It is an interprime number because it is at equal distance from previous prime (81751829) and next prime (81751837).

It can be written as a sum of positive squares in 2 ways, for example, as 33143049 + 48608784 = 5757^2 + 6972^2 .

It is not a de Polignac number, because 81751833 - 2² = 81751829 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81751837) 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 11 ways as a sum of consecutive naturals, for example, 122418 + ... + 123083.

It is an arithmetic number, because the mean of its divisors is an integer number (10106499).

Almost surely, 2^81751833 is an apocalyptic number.

It is an amenable number.

81751833 is a deficient number, since it is larger than the sum of its proper divisors (39526155).

81751833 is a wasteful number, since it uses less digits than its factorization.

81751833 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245544 (or 245541 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 81751833 is about 9041.6720245760. The cubic root of 81751833 is about 434.0094305185.

It can be divided in two parts, 817 and 51833, that added together give a triangular number (52650 = T₃₂₄).

The spelling of 81751833 in words is "eighty-one million, seven hundred fifty-one thousand, eight hundred thirty-three".