212211581 has 2 divisors, whose sum is σ = 212211582. Its totient is φ = 212211580.

The previous prime is 212211553. The next prime is 212211583. The reversal of 212211581 is 185112212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 186759556 + 25452025 = 13666^2 + 5045^2 .

It is a cyclic number.

It is not a de Polignac number, because 212211581 - 2²⁶ = 145102717 is a prime.

It is a super-2 number, since 2×212211581² = 90067510221039122, which contains 22 as substring.

Together with 212211583, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212211583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106105790 + 106105791.

It is an arithmetic number, because the mean of its divisors is an integer number (106105791).

Almost surely, 2^212211581 is an apocalyptic number.

It is an amenable number.

212211581 is a deficient number, since it is larger than the sum of its proper divisors (1).

212211581 is an equidigital number, since it uses as much as digits as its factorization.

212211581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 320, while the sum is 23.

The square root of 212211581 is about 14567.4836879950. The cubic root of 212211581 is about 596.4714947241.

Adding to 212211581 its reverse (185112212), we get a palindrome (397323793).

The spelling of 212211581 in words is "two hundred twelve million, two hundred eleven thousand, five hundred eighty-one".