21221212022201 has 4 divisors (see below), whose sum is σ = 21225552630900. Its totient is φ = 21216871413504.

The previous prime is 21221212022167. The next prime is 21221212022203. The reversal of 21221212022201 is 10222021212212.

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 13407644106025 + 7813567916176 = 3661645^2 + 2795276^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221212022201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221212022203) 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, 2170297016 + ... + 2170306793.

It is an arithmetic number, because the mean of its divisors is an integer number (5306388157725).

Almost surely, 2^{21221212022201} is an apocalyptic number.

It is an amenable number.

21221212022201 is a deficient number, since it is larger than the sum of its proper divisors (4340608699).

21221212022201 is an equidigital number, since it uses as much as digits as its factorization.

21221212022201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4340608698.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21221212022201 its reverse (10222021212212), we get a palindrome (31443233234413).

The spelling of 21221212022201 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twelve million, twenty-two thousand, two hundred one".