21000210012121 has 4 divisors (see below), whose sum is σ = 21058706419200. Its totient is φ = 20941713605044.

The previous prime is 21000210012079. The next prime is 21000210012143. The reversal of 21000210012121 is 12121001200012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21000210012121 - 2¹⁹ = 21000209487833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21000210052121) 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, 29248203001 + ... + 29248203718.

It is an arithmetic number, because the mean of its divisors is an integer number (5264676604800).

Almost surely, 2^{21000210012121} is an apocalyptic number.

It is an amenable number.

21000210012121 is a deficient number, since it is larger than the sum of its proper divisors (58496407079).

21000210012121 is an equidigital number, since it uses as much as digits as its factorization.

21000210012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58496407078.

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

Adding to 21000210012121 its reverse (12121001200012), we get a palindrome (33121211212133).

The spelling of 21000210012121 in words is "twenty-one trillion, two hundred ten million, twelve thousand, one hundred twenty-one".