20121221129 has 2 divisors, whose sum is σ = 20121221130.
Its totient is φ = 20121221128.
The previous prime is 20121221117. The next prime is 20121221137. The reversal of 20121221129 is 92112212102.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 20120855104 + 366025 = 141848^2 + 605^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-20121221129 is a prime.
It is not a weakly prime, because it can be changed into another prime (20121271129) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060610564 + 10060610565.
It is an arithmetic number, because the mean of its divisors is an integer number (10060610565).
Almost surely, 220121221129 is an apocalyptic number.
It is an amenable number.
20121221129 is a deficient number, since it is larger than the sum of its proper divisors (1).
20121221129 is an equidigital number, since it uses as much as digits as its factorization.
20121221129 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 23.
The spelling of 20121221129 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-one thousand, one hundred twenty-nine".