81756135 has 24 divisors (see below), whose sum is σ = 146961360. Its totient is φ = 43602624.

The previous prime is 81756127. The next prime is 81756139. The reversal of 81756135 is 53165718.

It is not a de Polignac number, because 81756135 - 2³ = 81756127 is a prime.

It is a super-2 number, since 2×81756135² = 13368131220276450, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81756135.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81756139) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 32430 + ... + 34859.

It is an arithmetic number, because the mean of its divisors is an integer number (6123390).

Almost surely, 2^81756135 is an apocalyptic number.

81756135 is a deficient number, since it is larger than the sum of its proper divisors (65205225).

81756135 is an equidigital number, since it uses as much as digits as its factorization.

81756135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67309 (or 67297 counting only the distinct ones).

The product of its digits is 25200, while the sum is 36.

The square root of 81756135 is about 9041.9099199229. The cubic root of 81756135 is about 434.0170432971.

The spelling of 81756135 in words is "eighty-one million, seven hundred fifty-six thousand, one hundred thirty-five".