21213211110 has 128 divisors (see below), whose sum is σ = 64354397184. Its totient is φ = 4354767360.

The previous prime is 21213211087. The next prime is 21213211111. The reversal of 21213211110 is 1111231212.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21213211110.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213211111) 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, 3996 + ... + 206015.

It is an arithmetic number, because the mean of its divisors is an integer number (502768728).

Almost surely, 2^21213211110 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21213211110, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32177198592).

21213211110 is an abundant number, since it is smaller than the sum of its proper divisors (43141186074).

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

21213211110 is a wasteful number, since it uses less digits than its factorization.

21213211110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210078.

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 21213211110 its reverse (1111231212), we get a palindrome (22324442322).

The spelling of 21213211110 in words is "twenty-one billion, two hundred thirteen million, two hundred eleven thousand, one hundred ten".