81810522501818 has 128 divisors (see below), whose sum is σ = 139539327713280. Its totient is φ = 35658411909120.

The previous prime is 81810522501739. The next prime is 81810522501901.

81810522501818 is nontrivially palindromic in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2637417113 + ... + 2637448131.

It is an arithmetic number, because the mean of its divisors is an integer number (1090150997760).

Almost surely, 2^{81810522501818} is an apocalyptic number.

81810522501818 is a deficient number, since it is larger than the sum of its proper divisors (57728805211462).

81810522501818 is a wasteful number, since it uses less digits than its factorization.

81810522501818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31492.

The product of its (nonzero) digits is 409600, while the sum is 50.

The spelling of 81810522501818 in words is "eighty-one trillion, eight hundred ten billion, five hundred twenty-two million, five hundred one thousand, eight hundred eighteen".