40206409 has 2 divisors, whose sum is σ = 40206410. Its totient is φ = 40206408.

The previous prime is 40206407. The next prime is 40206421. The reversal of 40206409 is 90460204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39879225 + 327184 = 6315^2 + 572^2 .

It is a cyclic number.

It is not a de Polignac number, because 40206409 - 2¹ = 40206407 is a prime.

Together with 40206407, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (40206401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20103204 + 20103205.

It is an arithmetic number, because the mean of its divisors is an integer number (20103205).

Almost surely, 2^40206409 is an apocalyptic number.

It is an amenable number.

40206409 is a deficient number, since it is larger than the sum of its proper divisors (1).

40206409 is an equidigital number, since it uses as much as digits as its factorization.

40206409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 40206409 is about 6340.8523874949. The cubic root of 40206409 is about 342.5824377546.

The spelling of 40206409 in words is "forty million, two hundred six thousand, four hundred nine".