21123235019 has 2 divisors, whose sum is σ = 21123235020. Its totient is φ = 21123235018.

The previous prime is 21123234907. The next prime is 21123235031. The reversal of 21123235019 is 91053232112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21123235019 - 2²⁴ = 21106457803 is a prime.

It is a super-2 number, since 2×21123235019² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21123234982 and 21123235000.

It is not a weakly prime, because it can be changed into another prime (21123235069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561617509 + 10561617510.

It is an arithmetic number, because the mean of its divisors is an integer number (10561617510).

Almost surely, 2^21123235019 is an apocalyptic number.

21123235019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123235019 is an equidigital number, since it uses as much as digits as its factorization.

21123235019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 29.

The spelling of 21123235019 in words is "twenty-one billion, one hundred twenty-three million, two hundred thirty-five thousand, nineteen".