221221001231 has 2 divisors, whose sum is σ = 221221001232. Its totient is φ = 221221001230.

The previous prime is 221221001219. The next prime is 221221001249. The reversal of 221221001231 is 132100122122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221221001231 - 2¹⁸ = 221220739087 is a prime.

It is a super-2 number, since 2×221221001231² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221221001431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610500615 + 110610500616.

It is an arithmetic number, because the mean of its divisors is an integer number (110610500616).

Almost surely, 2^221221001231 is an apocalyptic number.

221221001231 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221001231 is an equidigital number, since it uses as much as digits as its factorization.

221221001231 is an odious number, because the sum of its binary digits is odd.

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

Adding to 221221001231 its reverse (132100122122), we get a palindrome (353321123353).

The spelling of 221221001231 in words is "two hundred twenty-one billion, two hundred twenty-one million, one thousand, two hundred thirty-one".