20101221112121 has 2 divisors, whose sum is σ = 20101221112122. Its totient is φ = 20101221112120.

The previous prime is 20101221112111. The next prime is 20101221112187. The reversal of 20101221112121 is 12121112210102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16577112250000 + 3524108862121 = 4071500^2 + 1877261^2 .

It is a cyclic number.

It is not a de Polignac number, because 20101221112121 - 2³⁰ = 20100147370297 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20101221112121.

It is not a weakly prime, because it can be changed into another prime (20101221112111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10050610556060 + 10050610556061.

It is an arithmetic number, because the mean of its divisors is an integer number (10050610556061).

Almost surely, 2^{20101221112121} is an apocalyptic number.

It is an amenable number.

20101221112121 is a deficient number, since it is larger than the sum of its proper divisors (1).

20101221112121 is an equidigital number, since it uses as much as digits as its factorization.

20101221112121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 20101221112121 its reverse (12121112210102), we get a palindrome (32222333322223).

The spelling of 20101221112121 in words is "twenty trillion, one hundred one billion, two hundred twenty-one million, one hundred twelve thousand, one hundred twenty-one".