81040018 has 16 divisors (see below), whose sum is σ = 123409440. Its totient is φ = 39907296.

The previous prime is 81039979. The next prime is 81040049. The reversal of 81040018 is 81004018.

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 7 ways as a sum of consecutive naturals, for example, 53905 + ... + 55387.

It is an arithmetic number, because the mean of its divisors is an integer number (7713090).

Almost surely, 2^81040018 is an apocalyptic number.

81040018 is a deficient number, since it is larger than the sum of its proper divisors (42369422).

81040018 is a wasteful number, since it uses less digits than its factorization.

81040018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1881.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 81040018 is about 9002.2229476946. Note that the first 3 decimals coincide. The cubic root of 81040018 is about 432.7461136121.

The spelling of 81040018 in words is "eighty-one million, forty thousand, eighteen".