21000100129 has 2 divisors, whose sum is σ = 21000100130. Its totient is φ = 21000100128.

The previous prime is 21000100111. The next prime is 21000100139. The reversal of 21000100129 is 92100100012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10811216529 + 10188883600 = 103977^2 + 100940^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000100129 - 2⁵ = 21000100097 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000100139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500050064 + 10500050065.

It is an arithmetic number, because the mean of its divisors is an integer number (10500050065).

Almost surely, 2^21000100129 is an apocalyptic number.

It is an amenable number.

21000100129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000100129 is an equidigital number, since it uses as much as digits as its factorization.

21000100129 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 16.

The spelling of 21000100129 in words is "twenty-one billion, one hundred thousand, one hundred twenty-nine".