19986871 has 2 divisors, whose sum is σ = 19986872. Its totient is φ = 19986870.

The previous prime is 19986817. The next prime is 19986877. The reversal of 19986871 is 17868991.

Together with previous prime (19986817) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19986871 - 2⁹ = 19986359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19986877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9993435 + 9993436.

It is an arithmetic number, because the mean of its divisors is an integer number (9993436).

Almost surely, 2^19986871 is an apocalyptic number.

19986871 is a deficient number, since it is larger than the sum of its proper divisors (1).

19986871 is an equidigital number, since it uses as much as digits as its factorization.

19986871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 49.

The square root of 19986871 is about 4470.6678472014. The cubic root of 19986871 is about 271.3823526764.

The spelling of 19986871 in words is "nineteen million, nine hundred eighty-six thousand, eight hundred seventy-one".