21569040 has 120 divisors (see below), whose sum is σ = 75006360. Its totient is φ = 5548032.

The previous prime is 21569027. The next prime is 21569059. The reversal of 21569040 is 4096512.

It can be written as a sum of positive squares in 4 ways, for example, as 7551504 + 14017536 = 2748^2 + 3744^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a junction number, because it is equal to n+sod(n) for n = 21568995 and 21569013.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20364 + ... + 21396.

It is an arithmetic number, because the mean of its divisors is an integer number (625053).

Almost surely, 2^21569040 is an apocalyptic number.

21569040 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 21569040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37503180).

21569040 is an abundant number, since it is smaller than the sum of its proper divisors (53437320).

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

21569040 is a wasteful number, since it uses less digits than its factorization.

21569040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1081 (or 1072 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 21569040 is about 4644.2480553907. The cubic root of 21569040 is about 278.3622075136.

The spelling of 21569040 in words is "twenty-one million, five hundred sixty-nine thousand, forty".