1820989 has 6 divisors (see below), whose sum is σ = 1934714. Its totient is φ = 1713600.

The previous prime is 1820983. The next prime is 1820999. The reversal of 1820989 is 9890281.

1820989 is nontrivially palindromic in base 6.

It can be written as a sum of positive squares in 3 ways, for example, as 840889 + 980100 = 917^2 + 990^2 .

It is not a de Polignac number, because 1820989 - 2⁵ = 1820957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820983) 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 5 ways as a sum of consecutive naturals, for example, 2862 + ... + 3439.

2^1820989 is an apocalyptic number.

It is an amenable number.

1820989 is a deficient number, since it is larger than the sum of its proper divisors (113725).

1820989 is an equidigital number, since it uses as much as digits as its factorization.

1820989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6335 (or 6318 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 37.

The square root of 1820989 is about 1349.4402543277. The cubic root of 1820989 is about 122.1150263350.

It can be divided in two parts, 1820 and 989, that added together give a square (2809 = 53²).

The spelling of 1820989 in words is "one million, eight hundred twenty thousand, nine hundred eighty-nine".