21243340819 has 2 divisors, whose sum is σ = 21243340820. Its totient is φ = 21243340818.

The previous prime is 21243340747. The next prime is 21243340831. The reversal of 21243340819 is 91804334212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21243340819 - 2²⁹ = 20706469907 is a prime.

It is a super-2 number, since 2×21243340819² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21243440819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621670409 + 10621670410.

It is an arithmetic number, because the mean of its divisors is an integer number (10621670410).

Almost surely, 2^21243340819 is an apocalyptic number.

21243340819 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243340819 is an equidigital number, since it uses as much as digits as its factorization.

21243340819 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 37.

The spelling of 21243340819 in words is "twenty-one billion, two hundred forty-three million, three hundred forty thousand, eight hundred nineteen".