18859639 has 2 divisors, whose sum is σ = 18859640. Its totient is φ = 18859638.

The previous prime is 18859637. The next prime is 18859649. The reversal of 18859639 is 93695881.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18859639 - 2¹ = 18859637 is a prime.

Together with 18859637, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18859592 and 18859601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18859637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9429819 + 9429820.

It is an arithmetic number, because the mean of its divisors is an integer number (9429820).

Almost surely, 2^18859639 is an apocalyptic number.

18859639 is a deficient number, since it is larger than the sum of its proper divisors (1).

18859639 is an equidigital number, since it uses as much as digits as its factorization.

18859639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 466560, while the sum is 49.

The square root of 18859639 is about 4342.7685869731. The cubic root of 18859639 is about 266.1814532555.

The spelling of 18859639 in words is "eighteen million, eight hundred fifty-nine thousand, six hundred thirty-nine".