21200211112121 has 16 divisors (see below), whose sum is σ = 21613276335888. Its totient is φ = 20789355724800.

The previous prime is 21200211112111. The next prime is 21200211112151. The reversal of 21200211112121 is 12121111200212.

It can be written as a sum of positive squares in 8 ways, for example, as 120992665600 + 21079218446521 = 347840^2 + 4591211^2 .

It is a cyclic number.

It is not a de Polignac number, because 21200211112121 - 2¹⁴ = 21200211095737 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21200211112121.

It is not an unprimeable number, because it can be changed into a prime (21200211112111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26070941 + ... + 26871813.

It is an arithmetic number, because the mean of its divisors is an integer number (1350829770993).

Almost surely, 2^{21200211112121} is an apocalyptic number.

It is an amenable number.

21200211112121 is a deficient number, since it is larger than the sum of its proper divisors (413065223767).

21200211112121 is an equidigital number, since it uses as much as digits as its factorization.

21200211112121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 802252.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21200211112121 its reverse (12121111200212), we get a palindrome (33321322312333).

The spelling of 21200211112121 in words is "twenty-one trillion, two hundred billion, two hundred eleven million, one hundred twelve thousand, one hundred twenty-one".