42221209 has 2 divisors, whose sum is σ = 42221210. Its totient is φ = 42221208.

The previous prime is 42221203. The next prime is 42221219. The reversal of 42221209 is 90212224.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40921609 + 1299600 = 6397^2 + 1140^2 .

It is a cyclic number.

It is not a de Polignac number, because 42221209 - 2⁹ = 42220697 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42221209.

It is not a weakly prime, because it can be changed into another prime (42221203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21110604 + 21110605.

It is an arithmetic number, because the mean of its divisors is an integer number (21110605).

Almost surely, 2^42221209 is an apocalyptic number.

It is an amenable number.

42221209 is a deficient number, since it is larger than the sum of its proper divisors (1).

42221209 is an equidigital number, since it uses as much as digits as its factorization.

42221209 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 42221209 is about 6497.7849302666. The cubic root of 42221209 is about 348.2118568401.

The spelling of 42221209 in words is "forty-two million, two hundred twenty-one thousand, two hundred nine".