19491019 has 2 divisors, whose sum is σ = 19491020. Its totient is φ = 19491018.

The previous prime is 19491011. The next prime is 19491023. The reversal of 19491019 is 91019491.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (91019491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19491019 - 2³ = 19491011 is a prime.

It is a super-2 number, since 2×19491019² = 759799643316722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19491011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9745509 + 9745510.

It is an arithmetic number, because the mean of its divisors is an integer number (9745510).

Almost surely, 2^19491019 is an apocalyptic number.

19491019 is a deficient number, since it is larger than the sum of its proper divisors (1).

19491019 is an equidigital number, since it uses as much as digits as its factorization.

19491019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 34.

The square root of 19491019 is about 4414.8634180459. The cubic root of 19491019 is about 269.1193023509.

The spelling of 19491019 in words is "nineteen million, four hundred ninety-one thousand, nineteen".