19243921 has 2 divisors, whose sum is σ = 19243922. Its totient is φ = 19243920.

The previous prime is 19243879. The next prime is 19243933. The reversal of 19243921 is 12934291.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18835600 + 408321 = 4340^2 + 639^2 .

It is an emirp because it is prime and its reverse (12934291) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19243921 - 2¹⁹ = 18719633 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19243951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9621960 + 9621961.

It is an arithmetic number, because the mean of its divisors is an integer number (9621961).

Almost surely, 2^19243921 is an apocalyptic number.

It is an amenable number.

19243921 is a deficient number, since it is larger than the sum of its proper divisors (1).

19243921 is an equidigital number, since it uses as much as digits as its factorization.

19243921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 31.

The square root of 19243921 is about 4386.7893726506. The cubic root of 19243921 is about 267.9772062370.

It can be divided in two parts, 19243 and 921, that added together give a square (20164 = 142²).

The spelling of 19243921 in words is "nineteen million, two hundred forty-three thousand, nine hundred twenty-one".