21343212 has 36 divisors (see below), whose sum is σ = 58856616. Its totient is φ = 6467520.

The previous prime is 21343187. The next prime is 21343243. The reversal of 21343212 is 21234312.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 26553 + ... + 27344.

It is an arithmetic number, because the mean of its divisors is an integer number (1634906).

Almost surely, 2^21343212 is an apocalyptic number.

21343212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21343212 is an abundant number, since it is smaller than the sum of its proper divisors (37513404).

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

21343212 is a wasteful number, since it uses less digits than its factorization.

21343212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53918 (or 53913 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21343212 is about 4619.8714267824. The cubic root of 21343212 is about 277.3873124148.

Adding to 21343212 its reverse (21234312), we get a palindrome (42577524).

Subtracting from 21343212 its reverse (21234312), we obtain a square (108900 = 330²).

It can be divided in two parts, 213432 and 12, that added together give a square (213444 = 462²).

The spelling of 21343212 in words is "twenty-one million, three hundred forty-three thousand, two hundred twelve".