1980409 has 2 divisors, whose sum is σ = 1980410. Its totient is φ = 1980408.

The previous prime is 1980401. The next prime is 1980413. The reversal of 1980409 is 9040891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1432809 + 547600 = 1197^2 + 740^2 .

It is an emirp because it is prime and its reverse (9040891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1980409 - 2³ = 1980401 is a prime.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (1980401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990204 + 990205.

It is an arithmetic number, because the mean of its divisors is an integer number (990205).

2^1980409 is an apocalyptic number.

It is an amenable number.

1980409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1980409 is an equidigital number, since it uses as much as digits as its factorization.

1980409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 1980409 is about 1407.2700522643. The cubic root of 1980409 is about 125.5793691688.

The spelling of 1980409 in words is "one million, nine hundred eighty thousand, four hundred nine".