21044124109 has 2 divisors, whose sum is σ = 21044124110. Its totient is φ = 21044124108.

The previous prime is 21044124089. The next prime is 21044124121. The reversal of 21044124109 is 90142144012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20621821609 + 422302500 = 143603^2 + 20550^2 .

It is a cyclic number.

It is not a de Polignac number, because 21044124109 - 2⁵ = 21044124077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21074124109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522062054 + 10522062055.

It is an arithmetic number, because the mean of its divisors is an integer number (10522062055).

Almost surely, 2^21044124109 is an apocalyptic number.

It is an amenable number.

21044124109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21044124109 is an equidigital number, since it uses as much as digits as its factorization.

21044124109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 28.

The spelling of 21044124109 in words is "twenty-one billion, forty-four million, one hundred twenty-four thousand, one hundred nine".