21201211211201 has 16 divisors (see below), whose sum is σ = 25082421531648. Its totient is φ = 17536438656000.

The previous prime is 21201211211197. The next prime is 21201211211237. The reversal of 21201211211201 is 10211211210212.

It is a cyclic number.

It is not a de Polignac number, because 21201211211201 - 2² = 21201211211197 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 21201211211201.

It is not an unprimeable number, because it can be changed into a prime (21201211211251) 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, 138310700 + ... + 138463901.

It is an arithmetic number, because the mean of its divisors is an integer number (1567651345728).

Almost surely, 2^{21201211211201} is an apocalyptic number.

It is an amenable number.

21201211211201 is a deficient number, since it is larger than the sum of its proper divisors (3881210320447).

21201211211201 is a wasteful number, since it uses less digits than its factorization.

21201211211201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276774992.

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

Adding to 21201211211201 its reverse (10211211210212), we get a palindrome (31412422421413).

The spelling of 21201211211201 in words is "twenty-one trillion, two hundred one billion, two hundred eleven million, two hundred eleven thousand, two hundred one".