19723139 has 2 divisors, whose sum is σ = 19723140. Its totient is φ = 19723138.

The previous prime is 19723129. The next prime is 19723141. The reversal of 19723139 is 93132791.

It is a strong prime.

It is an emirp because it is prime and its reverse (93132791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19723139 - 2²⁰ = 18674563 is a prime.

Together with 19723141, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 19723099 and 19723108.

It is not a weakly prime, because it can be changed into another prime (19723129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9861569 + 9861570.

It is an arithmetic number, because the mean of its divisors is an integer number (9861570).

Almost surely, 2^19723139 is an apocalyptic number.

19723139 is a deficient number, since it is larger than the sum of its proper divisors (1).

19723139 is an equidigital number, since it uses as much as digits as its factorization.

19723139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10206, while the sum is 35.

The square root of 19723139 is about 4441.0740817960. The cubic root of 19723139 is about 270.1834099044.

The spelling of 19723139 in words is "nineteen million, seven hundred twenty-three thousand, one hundred thirty-nine".