19920871 has 2 divisors, whose sum is σ = 19920872. Its totient is φ = 19920870.

The previous prime is 19920869. The next prime is 19920893. The reversal of 19920871 is 17802991.

It is a weak prime.

It is an emirp because it is prime and its reverse (17802991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19920871 - 2¹ = 19920869 is a prime.

It is a super-2 number, since 2×19920871² = 793682202797282, which contains 22 as substring.

Together with 19920869, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 19920871.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19920851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9960435 + 9960436.

It is an arithmetic number, because the mean of its divisors is an integer number (9960436).

Almost surely, 2^19920871 is an apocalyptic number.

19920871 is a deficient number, since it is larger than the sum of its proper divisors (1).

19920871 is an equidigital number, since it uses as much as digits as its factorization.

19920871 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 19920871 is about 4463.2802959259. The cubic root of 19920871 is about 271.0833065872.

The spelling of 19920871 in words is "nineteen million, nine hundred twenty thousand, eight hundred seventy-one".