21050829109 has 2 divisors, whose sum is σ = 21050829110. Its totient is φ = 21050829108.

The previous prime is 21050829083. The next prime is 21050829127. The reversal of 21050829109 is 90192805012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18502800625 + 2548028484 = 136025^2 + 50478^2 .

It is a cyclic number.

It is not a de Polignac number, because 21050829109 - 2⁵ = 21050829077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21050829509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525414554 + 10525414555.

It is an arithmetic number, because the mean of its divisors is an integer number (10525414555).

Almost surely, 2^21050829109 is an apocalyptic number.

It is an amenable number.

21050829109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21050829109 is an equidigital number, since it uses as much as digits as its factorization.

21050829109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 37.

The spelling of 21050829109 in words is "twenty-one billion, fifty million, eight hundred twenty-nine thousand, one hundred nine".