20121225161 has 2 divisors, whose sum is σ = 20121225162.
Its totient is φ = 20121225160.
The previous prime is 20121225101. The next prime is 20121225181. The reversal of 20121225161 is 16152212102.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 16270278025 + 3850947136 = 127555^2 + 62056^2
It is a cyclic number.
It is not a de Polignac number, because 20121225161 - 26 = 20121225097 is a prime.
It is a Sophie Germain prime.
It is a Curzon number.
It is not a weakly prime, because it can be changed into another prime (20121225101) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060612580 + 10060612581.
It is an arithmetic number, because the mean of its divisors is an integer number (10060612581).
Almost surely, 220121225161 is an apocalyptic number.
It is an amenable number.
20121225161 is a deficient number, since it is larger than the sum of its proper divisors (1).
20121225161 is an equidigital number, since it uses as much as digits as its factorization.
20121225161 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 480, while the sum is 23.
Adding to 20121225161 its reverse (16152212102), we get a palindrome (36273437263).
The spelling of 20121225161 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-five thousand, one hundred sixty-one".