42722221 has 2 divisors, whose sum is σ = 42722222. Its totient is φ = 42722220.

The previous prime is 42722219. The next prime is 42722233. The reversal of 42722221 is 12222724.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 36542025 + 6180196 = 6045^2 + 2486^2 .

It is a cyclic number.

It is not a de Polignac number, because 42722221 - 2¹ = 42722219 is a prime.

Together with 42722219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 42722192 and 42722201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42722291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21361110 + 21361111.

It is an arithmetic number, because the mean of its divisors is an integer number (21361111).

Almost surely, 2^42722221 is an apocalyptic number.

It is an amenable number.

42722221 is a deficient number, since it is larger than the sum of its proper divisors (1).

42722221 is an equidigital number, since it uses as much as digits as its factorization.

42722221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 896, while the sum is 22.

The square root of 42722221 is about 6536.2237568798. The cubic root of 42722221 is about 349.5837800575.

Adding to 42722221 its reverse (12222724), we get a palindrome (54944945).

The spelling of 42722221 in words is "forty-two million, seven hundred twenty-two thousand, two hundred twenty-one".