42401209 has 2 divisors, whose sum is σ = 42401210. Its totient is φ = 42401208.

The previous prime is 42401201. The next prime is 42401231. The reversal of 42401209 is 90210424.

It is an a-pointer prime, because the next prime (42401231) can be obtained adding 42401209 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40449600 + 1951609 = 6360^2 + 1397^2 .

It is a cyclic number.

It is not a de Polignac number, because 42401209 - 2³ = 42401201 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42401209.

It is not a weakly prime, because it can be changed into another prime (42401201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21200604 + 21200605.

It is an arithmetic number, because the mean of its divisors is an integer number (21200605).

Almost surely, 2^42401209 is an apocalyptic number.

It is an amenable number.

42401209 is a deficient number, since it is larger than the sum of its proper divisors (1).

42401209 is an equidigital number, since it uses as much as digits as its factorization.

42401209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 42401209 is about 6511.6210731276. The cubic root of 42401209 is about 348.7059945418.

The spelling of 42401209 in words is "forty-two million, four hundred one thousand, two hundred nine".