21601824 has 48 divisors (see below), whose sum is σ = 58034592. Its totient is φ = 7031808.

The previous prime is 21601819. The next prime is 21601831. The reversal of 21601824 is 42810612.

It is a tau number, because it is divible by the number of its divisors (48).

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

It is a junction number, because it is equal to n+sod(n) for n = 21601794 and 21601803.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1512 + ... + 6744.

It is an arithmetic number, because the mean of its divisors is an integer number (1209054).

Almost surely, 2^21601824 is an apocalyptic number.

21601824 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 21601824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29017296).

21601824 is an abundant number, since it is smaller than the sum of its proper divisors (36432768).

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

21601824 is a wasteful number, since it uses less digits than its factorization.

21601824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5289 (or 5281 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21601824 is about 4647.7762424626. The cubic root of 21601824 is about 278.5031689239.

The spelling of 21601824 in words is "twenty-one million, six hundred one thousand, eight hundred twenty-four".