81204618 has 16 divisors (see below), whose sum is σ = 177173856. Its totient is φ = 24607440.

The previous prime is 81204589. The next prime is 81204649. The reversal of 81204618 is 81640218.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 615121 + ... + 615252.

It is an arithmetic number, because the mean of its divisors is an integer number (11073366).

Almost surely, 2^81204618 is an apocalyptic number.

81204618 is an abundant number, since it is smaller than the sum of its proper divisors (95969238).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81204618 is a wasteful number, since it uses less digits than its factorization.

81204618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1230389.

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 81204618 is about 9011.3604966176. The cubic root of 81204618 is about 433.0388983433.

Subtracting 81204618 from its reverse (81640218), we obtain a square (435600 = 660²).

The spelling of 81204618 in words is "eighty-one million, two hundred four thousand, six hundred eighteen".