42209639 has 2 divisors, whose sum is σ = 42209640. Its totient is φ = 42209638.

The previous prime is 42209627. The next prime is 42209683. The reversal of 42209639 is 93690224.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 42209639 - 2¹⁶ = 42144103 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 42209599 and 42209608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42209689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21104819 + 21104820.

It is an arithmetic number, because the mean of its divisors is an integer number (21104820).

Almost surely, 2^42209639 is an apocalyptic number.

42209639 is a deficient number, since it is larger than the sum of its proper divisors (1).

42209639 is an equidigital number, since it uses as much as digits as its factorization.

42209639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 35.

The square root of 42209639 is about 6496.8945658676. The cubic root of 42209639 is about 348.1800467669.

The spelling of 42209639 in words is "forty-two million, two hundred nine thousand, six hundred thirty-nine".