21212404422 has 64 divisors (see below), whose sum is σ = 49190768640. Its totient is φ = 6030525600.

The previous prime is 21212404387. The next prime is 21212404427. The reversal of 21212404422 is 22440421212.

It is a happy number.

It is a super-2 number, since 2×21212404422² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21212404392 and 21212404401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212404427) 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, 47047 + ... + 211277.

It is an arithmetic number, because the mean of its divisors is an integer number (768605760).

Almost surely, 2^21212404422 is an apocalyptic number.

21212404422 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21212404422, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24595384320).

21212404422 is an abundant number, since it is smaller than the sum of its proper divisors (27978364218).

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

21212404422 is a wasteful number, since it uses less digits than its factorization.

21212404422 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164369.

The product of its (nonzero) digits is 2048, while the sum is 24.

Adding to 21212404422 its reverse (22440421212), we get a palindrome (43652825634).

The spelling of 21212404422 in words is "twenty-one billion, two hundred twelve million, four hundred four thousand, four hundred twenty-two".