19419797921 has 2 divisors, whose sum is σ = 19419797922. Its totient is φ = 19419797920.

The previous prime is 19419797863. The next prime is 19419797981. The reversal of 19419797921 is 12979791491.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19417029025 + 2768896 = 139345^2 + 1664^2 .

It is an emirp because it is prime and its reverse (12979791491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19419797921 - 2¹⁸ = 19419535777 is a prime.

It is a super-3 number, since 3×19419797921³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (19419797981) 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, 9709898960 + 9709898961.

It is an arithmetic number, because the mean of its divisors is an integer number (9709898961).

Almost surely, 2^19419797921 is an apocalyptic number.

It is an amenable number.

19419797921 is a deficient number, since it is larger than the sum of its proper divisors (1).

19419797921 is an equidigital number, since it uses as much as digits as its factorization.

19419797921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2571912, while the sum is 59.

The spelling of 19419797921 in words is "nineteen billion, four hundred nineteen million, seven hundred ninety-seven thousand, nine hundred twenty-one".