1989811 has 2 divisors, whose sum is σ = 1989812. Its totient is φ = 1989810.

The previous prime is 1989803. The next prime is 1989847. The reversal of 1989811 is 1189891.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1189891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1989811 - 2³ = 1989803 is a prime.

It is not a weakly prime, because it can be changed into another prime (1909811) 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 as a sum of consecutive naturals, namely, 994905 + 994906.

It is an arithmetic number, because the mean of its divisors is an integer number (994906).

2^1989811 is an apocalyptic number.

1989811 is a deficient number, since it is larger than the sum of its proper divisors (1).

1989811 is an equidigital number, since it uses as much as digits as its factorization.

1989811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 37.

The square root of 1989811 is about 1410.6066071021. The cubic root of 1989811 is about 125.7777850324. Note that the first 4 decimals are identical.

The spelling of 1989811 in words is "one million, nine hundred eighty-nine thousand, eight hundred eleven".