19999873 has 2 divisors, whose sum is σ = 19999874. Its totient is φ = 19999872.

The previous prime is 19999843. The next prime is 19999891. The reversal of 19999873 is 37899991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19998784 + 1089 = 4472^2 + 33^2 .

It is an emirp because it is prime and its reverse (37899991) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19999873 is a prime.

It is a super-2 number, since 2×19999873² = 799989840032258, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19999843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999936 + 9999937.

It is an arithmetic number, because the mean of its divisors is an integer number (9999937).

Almost surely, 2^19999873 is an apocalyptic number.

It is an amenable number.

19999873 is a deficient number, since it is larger than the sum of its proper divisors (1).

19999873 is an equidigital number, since it uses as much as digits as its factorization.

19999873 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1102248, while the sum is 55.

The square root of 19999873 is about 4472.1217559454. The cubic root of 19999873 is about 271.4411871065.

The spelling of 19999873 in words is "nineteen million, nine hundred ninety-nine thousand, eight hundred seventy-three".