21000120212129 has 2 divisors, whose sum is σ = 21000120212130. Its totient is φ = 21000120212128.

The previous prime is 21000120212111. The next prime is 21000120212161. The reversal of 21000120212129 is 92121202100012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18076782822400 + 2923337389729 = 4251680^2 + 1709777^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000120212129 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000120212179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500060106064 + 10500060106065.

It is an arithmetic number, because the mean of its divisors is an integer number (10500060106065).

Almost surely, 2^{21000120212129} is an apocalyptic number.

It is an amenable number.

21000120212129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000120212129 is an equidigital number, since it uses as much as digits as its factorization.

21000120212129 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 23.

The spelling of 21000120212129 in words is "twenty-one trillion, one hundred twenty million, two hundred twelve thousand, one hundred twenty-nine".