1800990 has 24 divisors (see below), whose sum is σ = 4682808. Its totient is φ = 480240.

The previous prime is 1800979. The next prime is 1801003. The reversal of 1800990 is 990081.

It is an Ulam number.

1800990 is a modest number, since divided by 990 gives 180 as remainder.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9916 + ... + 10095.

It is an arithmetic number, because the mean of its divisors is an integer number (195117).

2^1800990 is an apocalyptic number.

1800990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1800990 is an abundant number, since it is smaller than the sum of its proper divisors (2881818).

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

1800990 is a wasteful number, since it uses less digits than its factorization.

1800990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20024 (or 20021 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 1800990 is about 1342.0096869993. The cubic root of 1800990 is about 121.6663372314. Note that the first 3 decimals are identical.

The spelling of 1800990 in words is "one million, eight hundred thousand, nine hundred ninety".