21201111211201 has 4 divisors (see below), whose sum is σ = 21204723606100. Its totient is φ = 21197498816304.

The previous prime is 21201111211199. The next prime is 21201111211229. The reversal of 21201111211201 is 10211211110212.

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 1401325618176 + 19799785593025 = 1183776^2 + 4449695^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201111211201 - 2¹ = 21201111211199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21201111211601) 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, 1806188646 + ... + 1806200383.

It is an arithmetic number, because the mean of its divisors is an integer number (5301180901525).

Almost surely, 2^{21201111211201} is an apocalyptic number.

It is an amenable number.

21201111211201 is a deficient number, since it is larger than the sum of its proper divisors (3612394899).

21201111211201 is an equidigital number, since it uses as much as digits as its factorization.

21201111211201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3612394898.

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

Adding to 21201111211201 its reverse (10211211110212), we get a palindrome (31412322321413).

The spelling of 21201111211201 in words is "twenty-one trillion, two hundred one billion, one hundred eleven million, two hundred eleven thousand, two hundred one".