81818635 has 4 divisors (see below), whose sum is σ = 98182368. Its totient is φ = 65454904.

The previous prime is 81818623. The next prime is 81818687. The reversal of 81818635 is 53681818.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81818635 - 2¹⁷ = 81687563 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8181859 + ... + 8181868.

It is an arithmetic number, because the mean of its divisors is an integer number (24545592).

Almost surely, 2^81818635 is an apocalyptic number.

81818635 is a deficient number, since it is larger than the sum of its proper divisors (16363733).

81818635 is a wasteful number, since it uses less digits than its factorization.

81818635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16363732.

The product of its digits is 46080, while the sum is 40.

The square root of 81818635 is about 9045.3653878658. The cubic root of 81818635 is about 434.1276125969.

The spelling of 81818635 in words is "eighty-one million, eight hundred eighteen thousand, six hundred thirty-five".