21344520 has 64 divisors (see below), whose sum is σ = 67806720. Its totient is φ = 5356544.

The previous prime is 21344513. The next prime is 21344593. The reversal of 21344520 is 2544312.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3192 + ... + 7271.

It is an arithmetic number, because the mean of its divisors is an integer number (1059480).

Almost surely, 2^21344520 is an apocalyptic number.

21344520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21344520 is an abundant number, since it is smaller than the sum of its proper divisors (46462200).

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

21344520 is a wasteful number, since it uses less digits than its factorization.

21344520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10494 (or 10490 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 21344520 is about 4620.0129869947. The cubic root of 21344520 is about 277.3929787784.

Adding to 21344520 its reverse (2544312), we get a palindrome (23888832).

The spelling of 21344520 in words is "twenty-one million, three hundred forty-four thousand, five hundred twenty".