42208409 has 4 divisors (see below), whose sum is σ = 42329700. Its totient is φ = 42087120.

The previous prime is 42208403. The next prime is 42208417. The reversal of 42208409 is 90480224.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36638809 + 5569600 = 6053^2 + 2360^2 .

It is a cyclic number.

It is not a de Polignac number, because 42208409 - 2¹⁶ = 42142873 is a prime.

It is a super-2 number, since 2×42208409² = 3563099580622562, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (42208403) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60122 + ... + 60819.

It is an arithmetic number, because the mean of its divisors is an integer number (10582425).

Almost surely, 2^42208409 is an apocalyptic number.

It is an amenable number.

42208409 is a deficient number, since it is larger than the sum of its proper divisors (121291).

42208409 is a wasteful number, since it uses less digits than its factorization.

42208409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121290.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 42208409 is about 6496.7999045684. The cubic root of 42208409 is about 348.1766647146.

The spelling of 42208409 in words is "forty-two million, two hundred eight thousand, four hundred nine".