2639809 has 2 divisors, whose sum is σ = 2639810. Its totient is φ = 2639808.

The previous prime is 2639801. The next prime is 2639827. The reversal of 2639809 is 9089362.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2039184 + 600625 = 1428^2 + 775^2 .

It is a cyclic number.

It is not a de Polignac number, because 2639809 - 2³ = 2639801 is a prime.

It is not a weakly prime, because it can be changed into another prime (2639801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1319904 + 1319905.

It is an arithmetic number, because the mean of its divisors is an integer number (1319905).

2^2639809 is an apocalyptic number.

It is an amenable number.

2639809 is a deficient number, since it is larger than the sum of its proper divisors (1).

2639809 is an equidigital number, since it uses as much as digits as its factorization.

2639809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 2639809 is about 1624.7489036771. The cubic root of 2639809 is about 138.2051314622.

The spelling of 2639809 in words is "two million, six hundred thirty-nine thousand, eight hundred nine".