1819181820 has 24 divisors (see below), whose sum is σ = 5093709264. Its totient is φ = 485115136.

The previous prime is 1819181797. The next prime is 1819181831. The reversal of 1819181820 is 281819181.

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 7 ways as a sum of consecutive naturals, for example, 15159789 + ... + 15159908.

It is an arithmetic number, because the mean of its divisors is an integer number (212237886).

Almost surely, 2^1819181820 is an apocalyptic number.

1819181820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1819181820 is an abundant number, since it is smaller than the sum of its proper divisors (3274527444).

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

1819181820 is a wasteful number, since it uses less digits than its factorization.

1819181820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30319709 (or 30319707 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 39.

The square root of 1819181820 is about 42651.8677199487. The cubic root of 1819181820 is about 1220.7461663145.

The spelling of 1819181820 in words is "one billion, eight hundred nineteen million, one hundred eighty-one thousand, eight hundred twenty".