21345560 has 32 divisors (see below), whose sum is σ = 48263040. Its totient is φ = 8496384.

The previous prime is 21345539. The next prime is 21345589. The reversal of 21345560 is 6554312.

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 7 ways as a sum of consecutive naturals, for example, 7724 + ... + 10116.

It is an arithmetic number, because the mean of its divisors is an integer number (1508220).

Almost surely, 2^21345560 is an apocalyptic number.

21345560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21345560 is an abundant number, since it is smaller than the sum of its proper divisors (26917480).

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

21345560 is a wasteful number, since it uses less digits than its factorization.

21345560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2627 (or 2623 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 21345560 is about 4620.1255394199. The cubic root of 21345560 is about 277.3974839786.

Adding to 21345560 its reverse (6554312), we get a palindrome (27899872).

The spelling of 21345560 in words is "twenty-one million, three hundred forty-five thousand, five hundred sixty".