1980990 has 128 divisors (see below), whose sum is σ = 6220800. Its totient is φ = 443520.

The previous prime is 1980983. The next prime is 1980991. The reversal of 1980990 is 990891.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1980991) 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 63 ways as a sum of consecutive naturals, for example, 68296 + ... + 68324.

It is an arithmetic number, because the mean of its divisors is an integer number (48600).

2^1980990 is an apocalyptic number.

1980990 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 1980990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3110400).

1980990 is an abundant number, since it is smaller than the sum of its proper divisors (4239810).

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

1980990 is a wasteful number, since it uses less digits than its factorization.

1980990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79 (or 73 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The square root of 1980990 is about 1407.4764651674. The cubic root of 1980990 is about 125.5916485312.

Subtracting from 1980990 its reverse (990891), we obtain a palindrome (990099).

The spelling of 1980990 in words is "one million, nine hundred eighty thousand, nine hundred ninety".