21452424 has 64 divisors (see below), whose sum is σ = 61776000. Its totient is φ = 6081024.

The previous prime is 21452413. The next prime is 21452443. The reversal of 21452424 is 42425412.

It is a happy number.

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 = 21452394 and 21452403.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24604 + ... + 25460.

It is an arithmetic number, because the mean of its divisors is an integer number (965250).

Almost surely, 2^21452424 is an apocalyptic number.

21452424 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 21452424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30888000).

21452424 is an abundant number, since it is smaller than the sum of its proper divisors (40323576).

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

21452424 is a wasteful number, since it uses less digits than its factorization.

21452424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1022 (or 1018 counting only the distinct ones).

The product of its digits is 2560, while the sum is 24.

The square root of 21452424 is about 4631.6761544823. The cubic root of 21452424 is about 277.8596327420.

Adding to 21452424 its reverse (42425412), we get a palindrome (63877836).

The spelling of 21452424 in words is "twenty-one million, four hundred fifty-two thousand, four hundred twenty-four".