20002120121 has 2 divisors, whose sum is σ = 20002120122. Its totient is φ = 20002120120.

The previous prime is 20002120001. The next prime is 20002120139. The reversal of 20002120121 is 12102120002.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17886120121 + 2116000000 = 133739^2 + 46000^2 .

It is a cyclic number.

It is not a de Polignac number, because 20002120121 - 2³⁰ = 18928378297 is a prime.

It is not a weakly prime, because it can be changed into another prime (20002120141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10001060060 + 10001060061.

It is an arithmetic number, because the mean of its divisors is an integer number (10001060061).

Almost surely, 2^20002120121 is an apocalyptic number.

It is an amenable number.

20002120121 is a deficient number, since it is larger than the sum of its proper divisors (1).

20002120121 is an equidigital number, since it uses as much as digits as its factorization.

20002120121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20002120121 its reverse (12102120002), we get a palindrome (32104240123).

The spelling of 20002120121 in words is "twenty billion, two million, one hundred twenty thousand, one hundred twenty-one".