21212122122 has 24 divisors (see below), whose sum is σ = 45965411076. Its totient is φ = 7069813056.

The previous prime is 21212122081. The next prime is 21212122187. The reversal of 21212122122 is 22122121212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18728196201 + 2483925921 = 136851^2 + 49839^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21212122095 and 21212122104.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 80448 + ... + 221124.

Almost surely, 2^21212122122 is an apocalyptic number.

21212122122 is an abundant number, since it is smaller than the sum of its proper divisors (24753288954).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21212122122 is a wasteful number, since it uses less digits than its factorization.

21212122122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149062 (or 149059 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

Adding to 21212122122 its reverse (22122121212), we get a palindrome (43334243334).

The spelling of 21212122122 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-two thousand, one hundred twenty-two".