21312221201 has 2 divisors, whose sum is σ = 21312221202. Its totient is φ = 21312221200.

The previous prime is 21312221171. The next prime is 21312221213. The reversal of 21312221201 is 10212221312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21269305600 + 42915601 = 145840^2 + 6551^2 .

It is a cyclic number.

It is not a de Polignac number, because 21312221201 - 2²² = 21308026897 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21312221201.

It is not a weakly prime, because it can be changed into another prime (21312221221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656110600 + 10656110601.

It is an arithmetic number, because the mean of its divisors is an integer number (10656110601).

Almost surely, 2^21312221201 is an apocalyptic number.

It is an amenable number.

21312221201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312221201 is an equidigital number, since it uses as much as digits as its factorization.

21312221201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21312221201 its reverse (10212221312), we get a palindrome (31524442513).

The spelling of 21312221201 in words is "twenty-one billion, three hundred twelve million, two hundred twenty-one thousand, two hundred one".