21784514123 has 2 divisors, whose sum is σ = 21784514124. Its totient is φ = 21784514122.

The previous prime is 21784514117. The next prime is 21784514149. The reversal of 21784514123 is 32141548712.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21784514123 - 2⁴ = 21784514107 is a prime.

It is not a weakly prime, because it can be changed into another prime (21784514183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10892257061 + 10892257062.

It is an arithmetic number, because the mean of its divisors is an integer number (10892257062).

Almost surely, 2^21784514123 is an apocalyptic number.

21784514123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21784514123 is an equidigital number, since it uses as much as digits as its factorization.

21784514123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 53760, while the sum is 38.

The spelling of 21784514123 in words is "twenty-one billion, seven hundred eighty-four million, five hundred fourteen thousand, one hundred twenty-three".