21040584 has 64 divisors (see below), whose sum is σ = 56125440. Its totient is φ = 6557760.

The previous prime is 21040559. The next prime is 21040601. The reversal of 21040584 is 48504012.

It is a super-2 number, since 2×21040584² = 885412350122112, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

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, 25539 + ... + 26349.

It is an arithmetic number, because the mean of its divisors is an integer number (876960).

Almost surely, 2^21040584 is an apocalyptic number.

21040584 is a gapful number since it is divisible by the number (24) 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 21040584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28062720).

21040584 is an abundant number, since it is smaller than the sum of its proper divisors (35084856).

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

21040584 is a wasteful number, since it uses less digits than its factorization.

21040584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 890 (or 886 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 21040584 is about 4587.0016350553. The cubic root of 21040584 is about 276.0700305386.

Adding to 21040584 its reverse (48504012), we get a palindrome (69544596).

The spelling of 21040584 in words is "twenty-one million, forty thousand, five hundred eighty-four".