2101210121 has 2 divisors, whose sum is σ = 2101210122. Its totient is φ = 2101210120.

The previous prime is 2101210099. The next prime is 2101210123. The reversal of 2101210121 is 1210121012.

2101210121 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1213825600 + 887384521 = 34840^2 + 29789^2 .

It is a cyclic number.

It is not a de Polignac number, because 2101210121 - 2³⁰ = 1027468297 is a prime.

Together with 2101210123, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (2101210123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050605060 + 1050605061.

It is an arithmetic number, because the mean of its divisors is an integer number (1050605061).

Almost surely, 2^2101210121 is an apocalyptic number.

It is an amenable number.

2101210121 is a deficient number, since it is larger than the sum of its proper divisors (1).

2101210121 is an equidigital number, since it uses as much as digits as its factorization.

2101210121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 2101210121 is about 45838.9585505605. The cubic root of 2101210121 is about 1280.8250948562.

Adding to 2101210121 its reverse (1210121012), we get a palindrome (3311331133).

The spelling of 2101210121 in words is "two billion, one hundred one million, two hundred ten thousand, one hundred twenty-one".