18555850820 has 24 divisors (see below), whose sum is σ = 41964770904. Its totient is φ = 6851390976.

The previous prime is 18555850811. The next prime is 18555850861. The reversal of 18555850820 is 2805855581.

It can be written as a sum of positive squares in 4 ways, for example, as 1107025984 + 17448824836 = 33272^2 + 132094^2 .

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, 35684069 + ... + 35684588.

It is an arithmetic number, because the mean of its divisors is an integer number (1748532121).

Almost surely, 2^18555850820 is an apocalyptic number.

18555850820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18555850820 is an abundant number, since it is smaller than the sum of its proper divisors (23408920084).

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

18555850820 is a wasteful number, since it uses less digits than its factorization.

18555850820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71368679 (or 71368677 counting only the distinct ones).

The product of its (nonzero) digits is 640000, while the sum is 47.

The spelling of 18555850820 in words is "eighteen billion, five hundred fifty-five million, eight hundred fifty thousand, eight hundred twenty".