21212244210 has 64 divisors (see below), whose sum is σ = 52689014784. Its totient is φ = 5461708800.

The previous prime is 21212244191. The next prime is 21212244227. The reversal of 21212244210 is 1244221212.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30415 + ... + 208205.

It is an arithmetic number, because the mean of its divisors is an integer number (823265856).

Almost surely, 2^21212244210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21212244210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26344507392).

21212244210 is an abundant number, since it is smaller than the sum of its proper divisors (31476770574).

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

21212244210 is a wasteful number, since it uses less digits than its factorization.

21212244210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177939.

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

Adding to 21212244210 its reverse (1244221212), we get a palindrome (22456465422).

The spelling of 21212244210 in words is "twenty-one billion, two hundred twelve million, two hundred forty-four thousand, two hundred ten".