42221561 has 2 divisors, whose sum is σ = 42221562. Its totient is φ = 42221560.

The previous prime is 42221527. The next prime is 42221579. The reversal of 42221561 is 16512224.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41925625 + 295936 = 6475^2 + 544^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42221561 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (42220561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21110780 + 21110781.

It is an arithmetic number, because the mean of its divisors is an integer number (21110781).

Almost surely, 2^42221561 is an apocalyptic number.

It is an amenable number.

42221561 is a deficient number, since it is larger than the sum of its proper divisors (1).

42221561 is an equidigital number, since it uses as much as digits as its factorization.

42221561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 960, while the sum is 23.

The square root of 42221561 is about 6497.8120163637. The cubic root of 42221561 is about 348.2128245231.

Adding to 42221561 its reverse (16512224), we get a palindrome (58733785).

The spelling of 42221561 in words is "forty-two million, two hundred twenty-one thousand, five hundred sixty-one".