21213333210 has 128 divisors (see below), whose sum is σ = 56411023104. Its totient is φ = 5082255360.

The previous prime is 21213333203. The next prime is 21213333217. The reversal of 21213333210 is 1233331212.

It is an interprime number because it is at equal distance from previous prime (21213333203) and next prime (21213333217).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21213333217) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 989505 + ... + 1010715.

It is an arithmetic number, because the mean of its divisors is an integer number (440711118).

Almost surely, 2^21213333210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21213333210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28205511552).

21213333210 is an abundant number, since it is smaller than the sum of its proper divisors (35197689894).

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

21213333210 is a wasteful number, since it uses less digits than its factorization.

21213333210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21328.

The product of its (nonzero) digits is 648, while the sum is 21.

Adding to 21213333210 its reverse (1233331212), we get a palindrome (22446664422).

The spelling of 21213333210 in words is "twenty-one billion, two hundred thirteen million, three hundred thirty-three thousand, two hundred ten".