221002100121221 has 2 divisors, whose sum is σ = 221002100121222. Its totient is φ = 221002100121220.

The previous prime is 221002100121217. The next prime is 221002100121287. The reversal of 221002100121221 is 122121001200122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 191849508450625 + 29152591670596 = 13850975^2 + 5399314^2 .

It is a cyclic number.

It is not a de Polignac number, because 221002100121221 - 2² = 221002100121217 is a prime.

It is a super-2 number, since 2×221002100121221² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 221002100121221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221002100121211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110501050060610 + 110501050060611.

It is an arithmetic number, because the mean of its divisors is an integer number (110501050060611).

Almost surely, 2^{221002100121221} is an apocalyptic number.

It is an amenable number.

221002100121221 is a deficient number, since it is larger than the sum of its proper divisors (1).

221002100121221 is an equidigital number, since it uses as much as digits as its factorization.

221002100121221 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 17.

Adding to 221002100121221 its reverse (122121001200122), we get a palindrome (343123101321343).

The spelling of 221002100121221 in words is "two hundred twenty-one trillion, two billion, one hundred million, one hundred twenty-one thousand, two hundred twenty-one".