21010000212121 has 4 divisors (see below), whose sum is σ = 21195929417652. Its totient is φ = 20824071006592.

The previous prime is 21010000212101. The next prime is 21010000212163. The reversal of 21010000212121 is 12121200001012.

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 436418784400 + 20573581427721 = 660620^2 + 4535811^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010000212121 - 2²⁷ = 21009865994393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21010000212101) 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, 92964602596 + ... + 92964602821.

It is an arithmetic number, because the mean of its divisors is an integer number (5298982354413).

Almost surely, 2^{21010000212121} is an apocalyptic number.

It is an amenable number.

21010000212121 is a deficient number, since it is larger than the sum of its proper divisors (185929205531).

21010000212121 is a wasteful number, since it uses less digits than its factorization.

21010000212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185929205530.

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

Adding to 21010000212121 its reverse (12121200001012), we get a palindrome (33131200213133).

The spelling of 21010000212121 in words is "twenty-one trillion, ten billion, two hundred twelve thousand, one hundred twenty-one".