19886639 has 2 divisors, whose sum is σ = 19886640. Its totient is φ = 19886638.

The previous prime is 19886627. The next prime is 19886641. The reversal of 19886639 is 93668891.

It is a strong prime.

It is an emirp because it is prime and its reverse (93668891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19886639 - 2⁴ = 19886623 is a prime.

Together with 19886641, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19886689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9943319 + 9943320.

It is an arithmetic number, because the mean of its divisors is an integer number (9943320).

Almost surely, 2^19886639 is an apocalyptic number.

19886639 is a deficient number, since it is larger than the sum of its proper divisors (1).

19886639 is an equidigital number, since it uses as much as digits as its factorization.

19886639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 559872, while the sum is 50.

The square root of 19886639 is about 4459.4437993992. The cubic root of 19886639 is about 270.9279411541.

The spelling of 19886639 in words is "nineteen million, eight hundred eighty-six thousand, six hundred thirty-nine".