21210000211121 has 4 divisors (see below), whose sum is σ = 21210011751972. Its totient is φ = 21209988670272.

The previous prime is 21210000211117. The next prime is 21210000211151. The reversal of 21210000211121 is 12111200001212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 12840325555600 + 8369674655521 = 3583340^2 + 2893039^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210000211121 - 2² = 21210000211117 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210000211096 and 21210000211105.

It is not an unprimeable number, because it can be changed into a prime (21210000211151) 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, 2329916 + ... + 6917261.

It is an arithmetic number, because the mean of its divisors is an integer number (5302502937993).

Almost surely, 2^{21210000211121} is an apocalyptic number.

It is an amenable number.

21210000211121 is a deficient number, since it is larger than the sum of its proper divisors (11540851).

21210000211121 is an equidigital number, since it uses as much as digits as its factorization.

21210000211121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11540850.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21210000211121 its reverse (12111200001212), we get a palindrome (33321200212333).

The spelling of 21210000211121 in words is "twenty-one trillion, two hundred ten billion, two hundred eleven thousand, one hundred twenty-one".