19985671 has 2 divisors, whose sum is σ = 19985672. Its totient is φ = 19985670.

The previous prime is 19985627. The next prime is 19985681. The reversal of 19985671 is 17658991.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19985671 - 2⁷ = 19985543 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19985621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9992835 + 9992836.

It is an arithmetic number, because the mean of its divisors is an integer number (9992836).

Almost surely, 2^19985671 is an apocalyptic number.

19985671 is a deficient number, since it is larger than the sum of its proper divisors (1).

19985671 is an equidigital number, since it uses as much as digits as its factorization.

19985671 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 46.

The square root of 19985671 is about 4470.5336370505. The cubic root of 19985671 is about 271.3769213554.

The spelling of 19985671 in words is "nineteen million, nine hundred eighty-five thousand, six hundred seventy-one".