1818209840 has 40 divisors (see below), whose sum is σ = 4476008160. Its totient is φ = 684502016.

The previous prime is 1818209831. The next prime is 1818209879. The reversal of 1818209840 is 489028181.

It is a tau number, because it is divible by the number of its divisors (40).

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, 667100 + ... + 669819.

It is an arithmetic number, because the mean of its divisors is an integer number (111900204).

Almost surely, 2^1818209840 is an apocalyptic number.

1818209840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1818209840 is an abundant number, since it is smaller than the sum of its proper divisors (2657798320).

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

1818209840 is a wasteful number, since it uses less digits than its factorization.

1818209840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1336949 (or 1336943 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 41.

The square root of 1818209840 is about 42640.4718548001. The cubic root of 1818209840 is about 1220.5287146687.

The spelling of 1818209840 in words is "one billion, eight hundred eighteen million, two hundred nine thousand, eight hundred forty".