19018991 has 2 divisors, whose sum is σ = 19018992. Its totient is φ = 19018990.

The previous prime is 19018963. The next prime is 19019009. The reversal of 19018991 is 19981091.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19018991 - 2⁶ = 19018927 is a prime.

It is a Chen prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19018921) 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, 9509495 + 9509496.

It is an arithmetic number, because the mean of its divisors is an integer number (9509496).

Almost surely, 2^19018991 is an apocalyptic number.

19018991 is a deficient number, since it is larger than the sum of its proper divisors (1).

19018991 is an equidigital number, since it uses as much as digits as its factorization.

19018991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 38.

The square root of 19018991 is about 4361.0768165672. The cubic root of 19018991 is about 266.9290398568.

The spelling of 19018991 in words is "nineteen million, eighteen thousand, nine hundred ninety-one".