404240209 has 2 divisors, whose sum is σ = 404240210. Its totient is φ = 404240208.

The previous prime is 404240191. The next prime is 404240261. The reversal of 404240209 is 902042404.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216001809 + 188238400 = 14697^2 + 13720^2 .

It is a cyclic number.

It is not a de Polignac number, because 404240209 - 2²³ = 395851601 is a prime.

It is not a weakly prime, because it can be changed into another prime (404240299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202120104 + 202120105.

It is an arithmetic number, because the mean of its divisors is an integer number (202120105).

Almost surely, 2^404240209 is an apocalyptic number.

It is an amenable number.

404240209 is a deficient number, since it is larger than the sum of its proper divisors (1).

404240209 is an equidigital number, since it uses as much as digits as its factorization.

404240209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 404240209 is about 20105.7257765046. The cubic root of 404240209 is about 739.4006645878.

The spelling of 404240209 in words is "four hundred four million, two hundred forty thousand, two hundred nine".