21022213212 has 144 divisors (see below), whose sum is σ = 71348239872. Its totient is φ = 5040282240.

The previous prime is 21022213207. The next prime is 21022213213. The reversal of 21022213212 is 21231222012.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022213213) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 255648 + ... + 327719.

It is an arithmetic number, because the mean of its divisors is an integer number (495473888).

Almost surely, 2^21022213212 is an apocalyptic number.

21022213212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21022213212 is an abundant number, since it is smaller than the sum of its proper divisors (50326026660).

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

21022213212 is a wasteful number, since it uses less digits than its factorization.

21022213212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 583408 (or 583403 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21022213212 its reverse (21231222012), we get a palindrome (42253435224).

The spelling of 21022213212 in words is "twenty-one billion, twenty-two million, two hundred thirteen thousand, two hundred twelve".