2100100212121 has 4 divisors (see below), whose sum is σ = 2100228026292. Its totient is φ = 2099972397952.

The previous prime is 2100100212101. The next prime is 2100100212127. The reversal of 2100100212121 is 1212120010012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1510775306496 + 589324905625 = 1229136^2 + 767675^2 .

It is a cyclic number.

It is not a de Polignac number, because 2100100212121 - 2⁹ = 2100100211609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2100100212127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63882436 + ... + 63915301.

It is an arithmetic number, because the mean of its divisors is an integer number (525057006573).

Almost surely, 2^{2100100212121} is an apocalyptic number.

It is an amenable number.

2100100212121 is a deficient number, since it is larger than the sum of its proper divisors (127814171).

2100100212121 is a wasteful number, since it uses less digits than its factorization.

2100100212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127814170.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 2100100212121 its reverse (1212120010012), we get a palindrome (3312220222133).

The spelling of 2100100212121 in words is "two trillion, one hundred billion, one hundred million, two hundred twelve thousand, one hundred twenty-one".