21036024 has 56 divisors (see below), whose sum is σ = 59153160. Its totient is φ = 7010064.

The previous prime is 21036023. The next prime is 21036031. The reversal of 21036024 is 42063012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21035988 and 21036006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036023) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 4029 + ... + 7635.

Almost surely, 2^21036024 is an apocalyptic number.

21036024 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 21036024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29576580).

21036024 is an abundant number, since it is smaller than the sum of its proper divisors (38117136).

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

21036024 is an equidigital number, since it uses as much as digits as its factorization.

21036024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3631 (or 3612 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21036024 is about 4586.5045513986. The cubic root of 21036024 is about 276.0500854285.

Adding to 21036024 its reverse (42063012), we get a palindrome (63099036).

The spelling of 21036024 in words is "twenty-one million, thirty-six thousand, twenty-four".