42865639 has 2 divisors, whose sum is σ = 42865640. Its totient is φ = 42865638.

The previous prime is 42865621. The next prime is 42865643. The reversal of 42865639 is 93656824.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 42865639 - 2¹⁵ = 42832871 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 42865595 and 42865604.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42865699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21432819 + 21432820.

It is an arithmetic number, because the mean of its divisors is an integer number (21432820).

Almost surely, 2^42865639 is an apocalyptic number.

42865639 is a deficient number, since it is larger than the sum of its proper divisors (1).

42865639 is an equidigital number, since it uses as much as digits as its factorization.

42865639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 311040, while the sum is 43.

The square root of 42865639 is about 6547.1855785521. The cubic root of 42865639 is about 349.9745260371.

The spelling of 42865639 in words is "forty-two million, eight hundred sixty-five thousand, six hundred thirty-nine".