21560440 has 64 divisors (see below), whose sum is σ = 55728000. Its totient is φ = 7424640.

The previous prime is 21560431. The next prime is 21560467. The reversal of 21560440 is 4406512.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7071 + ... + 9649.

It is an arithmetic number, because the mean of its divisors is an integer number (870750).

Almost surely, 2^21560440 is an apocalyptic number.

21560440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21560440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27864000).

21560440 is an abundant number, since it is smaller than the sum of its proper divisors (34167560).

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

21560440 is a wasteful number, since it uses less digits than its factorization.

21560440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2620 (or 2616 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 21560440 is about 4643.3220866100. The cubic root of 21560440 is about 278.3252064352.

Adding to 21560440 its reverse (4406512), we get a palindrome (25966952).

It can be divided in two parts, 21560 and 440, that multiplied together give a square (9486400 = 3080²).

The spelling of 21560440 in words is "twenty-one million, five hundred sixty thousand, four hundred forty".