42542209 has 2 divisors, whose sum is σ = 42542210. Its totient is φ = 42542208.

The previous prime is 42542167. The next prime is 42542221. The reversal of 42542209 is 90224524.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39652209 + 2890000 = 6297^2 + 1700^2 .

It is a cyclic number.

It is not a de Polignac number, because 42542209 - 2²³ = 34153601 is a prime.

It is not a weakly prime, because it can be changed into another prime (42542909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21271104 + 21271105.

It is an arithmetic number, because the mean of its divisors is an integer number (21271105).

Almost surely, 2^42542209 is an apocalyptic number.

It is an amenable number.

42542209 is a deficient number, since it is larger than the sum of its proper divisors (1).

42542209 is an equidigital number, since it uses as much as digits as its factorization.

42542209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 42542209 is about 6522.4388843438. The cubic root of 42542209 is about 349.0920931669.

The spelling of 42542209 in words is "forty-two million, five hundred forty-two thousand, two hundred nine".