21020122129 has 2 divisors, whose sum is σ = 21020122130. Its totient is φ = 21020122128.

The previous prime is 21020122093. The next prime is 21020122147. The reversal of 21020122129 is 92122102012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12711435025 + 8308687104 = 112745^2 + 91152^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020122129 - 2⁷ = 21020122001 is a prime.

It is not a weakly prime, because it can be changed into another prime (21020122169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510061064 + 10510061065.

It is an arithmetic number, because the mean of its divisors is an integer number (10510061065).

Almost surely, 2^21020122129 is an apocalyptic number.

It is an amenable number.

21020122129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020122129 is an equidigital number, since it uses as much as digits as its factorization.

21020122129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 22.

The spelling of 21020122129 in words is "twenty-one billion, twenty million, one hundred twenty-two thousand, one hundred twenty-nine".