81810135 has 64 divisors (see below), whose sum is σ = 160704000. Its totient is φ = 39156480.

The previous prime is 81810133. The next prime is 81810161. The reversal of 81810135 is 53101818.

81810135 = 4043² + 4044² + ... + 4047².

It is not a de Polignac number, because 81810135 - 2¹ = 81810133 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 81810099 and 81810108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81810133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 131856 + ... + 132474.

It is an arithmetic number, because the mean of its divisors is an integer number (2511000).

Almost surely, 2^81810135 is an apocalyptic number.

81810135 is a deficient number, since it is larger than the sum of its proper divisors (78893865).

81810135 is a wasteful number, since it uses less digits than its factorization.

81810135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 733 (or 727 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 27.

The square root of 81810135 is about 9044.8955217846. The cubic root of 81810135 is about 434.1125784811.

The spelling of 81810135 in words is "eighty-one million, eight hundred ten thousand, one hundred thirty-five".