1899990 has 64 divisors (see below), whose sum is σ = 5253120. Its totient is φ = 488160.

The previous prime is 1899983. The next prime is 1900009. The reversal of 1899990 is 999981.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8257 + ... + 8483.

It is an arithmetic number, because the mean of its divisors is an integer number (82080).

2^1899990 is an apocalyptic number.

1899990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1899990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2626560).

1899990 is an abundant number, since it is smaller than the sum of its proper divisors (3353130).

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

1899990 is a wasteful number, since it uses less digits than its factorization.

1899990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 45.

The square root of 1899990 is about 1378.4012478230. The cubic root of 1899990 is about 123.8560156710.

Subtracting from 1899990 its reverse (999981), we obtain a palindrome (900009).

The spelling of 1899990 in words is "one million, eight hundred ninety-nine thousand, nine hundred ninety".