21020204129 has 2 divisors, whose sum is σ = 21020204130. Its totient is φ = 21020204128.

The previous prime is 21020204119. The next prime is 21020204201. The reversal of 21020204129 is 92140202012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20779799104 + 240405025 = 144152^2 + 15505^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020204129 - 2⁴ = 21020204113 is a prime.

It is not a weakly prime, because it can be changed into another prime (21020204119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510102064 + 10510102065.

It is an arithmetic number, because the mean of its divisors is an integer number (10510102065).

Almost surely, 2^21020204129 is an apocalyptic number.

It is an amenable number.

21020204129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020204129 is an equidigital number, since it uses as much as digits as its factorization.

21020204129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 23.

The spelling of 21020204129 in words is "twenty-one billion, twenty million, two hundred four thousand, one hundred twenty-nine".