21344406 has 32 divisors (see below), whose sum is σ = 44431200. Its totient is φ = 6827520.

The previous prime is 21344369. The next prime is 21344417. The reversal of 21344406 is 60444312.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41680 + ... + 42188.

It is an arithmetic number, because the mean of its divisors is an integer number (1388475).

Almost surely, 2^21344406 is an apocalyptic number.

21344406 is an abundant number, since it is smaller than the sum of its proper divisors (23086794).

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

21344406 is a wasteful number, since it uses less digits than its factorization.

21344406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784.

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 21344406 is about 4620.0006493506. Note that the first 3 decimals coincide. The cubic root of 21344406 is about 277.3924849302.

Adding to 21344406 its reverse (60444312), we get a palindrome (81788718).

The spelling of 21344406 in words is "twenty-one million, three hundred forty-four thousand, four hundred six".