211212222221221 has 16 divisors (see below), whose sum is σ = 229566616879600. Its totient is φ = 193159190274048.

The previous prime is 211212222221183. The next prime is 211212222221263. The reversal of 211212222221221 is 122122222212112.

It can be written as a sum of positive squares in 8 ways, for example, as 3994757718721 + 207217464502500 = 1998689^2 + 14395050^2 .

It is a cyclic number.

It is not a de Polignac number, because 211212222221221 - 2⁹ = 211212222220709 is a prime.

It is a super-2 number, since 2×211212222221221² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211212222221621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9210085 + ... + 22522213.

It is an arithmetic number, because the mean of its divisors is an integer number (14347913554975).

Almost surely, 2^{211212222221221} is an apocalyptic number.

It is an amenable number.

211212222221221 is a deficient number, since it is larger than the sum of its proper divisors (18354394658379).

211212222221221 is a wasteful number, since it uses less digits than its factorization.

211212222221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13323448.

The product of its digits is 1024, while the sum is 25.

Adding to 211212222221221 its reverse (122122222212112), we get a palindrome (333334444433333).

The spelling of 211212222221221 in words is "two hundred eleven trillion, two hundred twelve billion, two hundred twenty-two million, two hundred twenty-one thousand, two hundred twenty-one".