212122222221 has 32 divisors (see below), whose sum is σ = 357506076928. Its totient is φ = 108864622080.

The previous prime is 212122222183. The next prime is 212122222231. The reversal of 212122222221 is 122222221212.

It is not a de Polignac number, because 212122222221 - 2⁹ = 212122221709 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212122222231) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10489960 + ... + 10510161.

It is an arithmetic number, because the mean of its divisors is an integer number (11172064904).

Almost surely, 2^212122222221 is an apocalyptic number.

212122222221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

212122222221 is a deficient number, since it is larger than the sum of its proper divisors (145383854707).

212122222221 is a wasteful number, since it uses less digits than its factorization.

212122222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21000181.

The product of its digits is 512, while the sum is 21.

Adding to 212122222221 its reverse (122222221212), we get a palindrome (334344443433).

The spelling of 212122222221 in words is "two hundred twelve billion, one hundred twenty-two million, two hundred twenty-two thousand, two hundred twenty-one".