42221909 has 2 divisors, whose sum is σ = 42221910. Its totient is φ = 42221908.

The previous prime is 42221899. The next prime is 42221911. The reversal of 42221909 is 90912224.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22061809 + 20160100 = 4697^2 + 4490^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42221909 is a prime.

Together with 42221911, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42221929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21110954 + 21110955.

It is an arithmetic number, because the mean of its divisors is an integer number (21110955).

Almost surely, 2^42221909 is an apocalyptic number.

It is an amenable number.

42221909 is a deficient number, since it is larger than the sum of its proper divisors (1).

42221909 is an equidigital number, since it uses as much as digits as its factorization.

42221909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 42221909 is about 6497.8387945532. The cubic root of 42221909 is about 348.2137812044.

The spelling of 42221909 in words is "forty-two million, two hundred twenty-one thousand, nine hundred nine".