19919519 has 2 divisors, whose sum is σ = 19919520. Its totient is φ = 19919518.

The previous prime is 19919509. The next prime is 19919531. The reversal of 19919519 is 91591991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19919519 - 2¹⁶ = 19853983 is a prime.

It is a super-2 number, since 2×19919519² = 793574474382722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 19919519.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19919509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9959759 + 9959760.

It is an arithmetic number, because the mean of its divisors is an integer number (9959760).

Almost surely, 2^19919519 is an apocalyptic number.

19919519 is a deficient number, since it is larger than the sum of its proper divisors (1).

19919519 is an equidigital number, since it uses as much as digits as its factorization.

19919519 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32805, while the sum is 44.

The square root of 19919519 is about 4463.1288352455. The cubic root of 19919519 is about 271.0771737743.

The spelling of 19919519 in words is "nineteen million, nine hundred nineteen thousand, five hundred nineteen".