42542221 has 2 divisors, whose sum is σ = 42542222. Its totient is φ = 42542220.

The previous prime is 42542209. The next prime is 42542243. The reversal of 42542221 is 12224524.

It is an a-pointer prime, because the next prime (42542243) can be obtained adding 42542221 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., 24860196 + 17682025 = 4986^2 + 4205^2 .

It is a cyclic number.

It is not a de Polignac number, because 42542221 - 2²⁵ = 8987789 is a prime.

It is a super-2 number, since 2×42542221² = 3619681135225682, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 42542192 and 42542201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42542251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21271110 + 21271111.

It is an arithmetic number, because the mean of its divisors is an integer number (21271111).

Almost surely, 2^42542221 is an apocalyptic number.

It is an amenable number.

42542221 is a deficient number, since it is larger than the sum of its proper divisors (1).

42542221 is an equidigital number, since it uses as much as digits as its factorization.

42542221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1280, while the sum is 22.

The square root of 42542221 is about 6522.4398042450. The cubic root of 42542221 is about 349.0921259900.

Adding to 42542221 its reverse (12224524), we get a palindrome (54766745).

The spelling of 42542221 in words is "forty-two million, five hundred forty-two thousand, two hundred twenty-one".