40208809 has 2 divisors, whose sum is σ = 40208810. Its totient is φ = 40208808.

The previous prime is 40208803. The next prime is 40208837. The reversal of 40208809 is 90880204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 32171584 + 8037225 = 5672^2 + 2835^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40208809 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (40208803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20104404 + 20104405.

It is an arithmetic number, because the mean of its divisors is an integer number (20104405).

Almost surely, 2^40208809 is an apocalyptic number.

It is an amenable number.

40208809 is a deficient number, since it is larger than the sum of its proper divisors (1).

40208809 is an equidigital number, since it uses as much as digits as its factorization.

40208809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 40208809 is about 6341.0416336750. The cubic root of 40208809 is about 342.5892540932.

It can be divided in two parts, 40 and 208809, that added together give a square (208849 = 457²).

The spelling of 40208809 in words is "forty million, two hundred eight thousand, eight hundred nine".