21124144309 has 2 divisors, whose sum is σ = 21124144310. Its totient is φ = 21124144308.

The previous prime is 21124144169. The next prime is 21124144343. The reversal of 21124144309 is 90344142112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21105697284 + 18447025 = 145278^2 + 4295^2 .

It is a cyclic number.

It is not a de Polignac number, because 21124144309 - 2¹⁷ = 21124013237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21124144409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10562072154 + 10562072155.

It is an arithmetic number, because the mean of its divisors is an integer number (10562072155).

Almost surely, 2^21124144309 is an apocalyptic number.

It is an amenable number.

21124144309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21124144309 is an equidigital number, since it uses as much as digits as its factorization.

21124144309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 31.

The spelling of 21124144309 in words is "twenty-one billion, one hundred twenty-four million, one hundred forty-four thousand, three hundred nine".