1990820 has 72 divisors (see below), whose sum is σ = 4919040. Its totient is φ = 673920.

The previous prime is 1990787. The next prime is 1990823. The reversal of 1990820 is 280991.

1990820 = 142² + 143² + ... + 206².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990823) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 64205 + ... + 64235.

It is an arithmetic number, because the mean of its divisors is an integer number (68320).

2^1990820 is an apocalyptic number.

1990820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1990820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2459520).

1990820 is an abundant number, since it is smaller than the sum of its proper divisors (2928220).

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

1990820 is a wasteful number, since it uses less digits than its factorization.

1990820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 1990820 is about 1410.9642093264. The cubic root of 1990820 is about 125.7990413795.

The spelling of 1990820 in words is "one million, nine hundred ninety thousand, eight hundred twenty".