221212210181 has 2 divisors, whose sum is σ = 221212210182. Its totient is φ = 221212210180.

The previous prime is 221212210169. The next prime is 221212210207. The reversal of 221212210181 is 181012212122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 215148473281 + 6063736900 = 463841^2 + 77870^2 .

It is a cyclic number.

It is not a de Polignac number, because 221212210181 - 2¹⁸ = 221211948037 is a prime.

It is a super-2 number, since 2×221212210181² (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 (221212210481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110606105090 + 110606105091.

It is an arithmetic number, because the mean of its divisors is an integer number (110606105091).

Almost surely, 2^221212210181 is an apocalyptic number.

It is an amenable number.

221212210181 is a deficient number, since it is larger than the sum of its proper divisors (1).

221212210181 is an equidigital number, since it uses as much as digits as its factorization.

221212210181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 23.

The spelling of 221212210181 in words is "two hundred twenty-one billion, two hundred twelve million, two hundred ten thousand, one hundred eighty-one".