221221212001 has 2 divisors, whose sum is σ = 221221212002. Its totient is φ = 221221212000.

The previous prime is 221221211941. The next prime is 221221212013. The reversal of 221221212001 is 100212122122.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 126433580625 + 94787631376 = 355575^2 + 307876^2 .

It is a cyclic number.

It is not a de Polignac number, because 221221212001 - 2²⁵ = 221187657569 is a prime.

It is not a weakly prime, because it can be changed into another prime (221221219001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610606000 + 110610606001.

It is an arithmetic number, because the mean of its divisors is an integer number (110610606001).

Almost surely, 2^221221212001 is an apocalyptic number.

It is an amenable number.

221221212001 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221212001 is an equidigital number, since it uses as much as digits as its factorization.

221221212001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 221221212001 its reverse (100212122122), we get a palindrome (321433334123).

The spelling of 221221212001 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred twelve thousand, one".