1801990 has 16 divisors (see below), whose sum is σ = 3286080. Its totient is φ = 711360.

The previous prime is 1801967. The next prime is 1801997. The reversal of 1801990 is 991081.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1801997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 351 + ... + 1930.

It is an arithmetic number, because the mean of its divisors is an integer number (205380).

2^1801990 is an apocalyptic number.

1801990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1801990 is a deficient number, since it is larger than the sum of its proper divisors (1484090).

1801990 is a wasteful number, since it uses less digits than its factorization.

1801990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2367.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 1801990 is about 1342.3822108476. The cubic root of 1801990 is about 121.6888514830.

The spelling of 1801990 in words is "one million, eight hundred one thousand, nine hundred ninety".