1818381820 has 48 divisors (see below), whose sum is σ = 3899595168. Its totient is φ = 712074240.

The previous prime is 1818381811. The next prime is 1818381839. The reversal of 1818381820 is 281838181.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 195475 + ... + 204565.

It is an arithmetic number, because the mean of its divisors is an integer number (81241566).

Almost surely, 2^1818381820 is an apocalyptic number.

1818381820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1818381820 is an abundant number, since it is smaller than the sum of its proper divisors (2081213348).

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

1818381820 is a wasteful number, since it uses less digits than its factorization.

1818381820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9310 (or 9308 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 40.

The square root of 1818381820 is about 42642.4884358312. The cubic root of 1818381820 is about 1220.5671957259.

The spelling of 1818381820 in words is "one billion, eight hundred eighteen million, three hundred eighty-one thousand, eight hundred twenty".