21201222101 has 2 divisors, whose sum is σ = 21201222102. Its totient is φ = 21201222100.

The previous prime is 21201222089. The next prime is 21201222193. The reversal of 21201222101 is 10122210212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20923333201 + 277888900 = 144649^2 + 16670^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201222101 - 2³⁰ = 20127480277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201222001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600611050 + 10600611051.

It is an arithmetic number, because the mean of its divisors is an integer number (10600611051).

Almost surely, 2^21201222101 is an apocalyptic number.

It is an amenable number.

21201222101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201222101 is an equidigital number, since it uses as much as digits as its factorization.

21201222101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21201222101 its reverse (10122210212), we get a palindrome (31323432313).

It can be divided in two parts, 2120 and 1222101, that added together give a palindrome (1224221).

The spelling of 21201222101 in words is "twenty-one billion, two hundred one million, two hundred twenty-two thousand, one hundred one".