21074424 has 128 divisors (see below), whose sum is σ = 65525760. Its totient is φ = 5511168.

The previous prime is 21074419. The next prime is 21074489. The reversal of 21074424 is 42447012.

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 = 21074394 and 21074403.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 134154 + ... + 134310.

It is an arithmetic number, because the mean of its divisors is an integer number (511920).

Almost surely, 2^21074424 is an apocalyptic number.

21074424 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 21074424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32762880).

21074424 is an abundant number, since it is smaller than the sum of its proper divisors (44451336).

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

21074424 is a wasteful number, since it uses less digits than its factorization.

21074424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237 (or 233 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 24.

The square root of 21074424 is about 4590.6888372008. The cubic root of 21074424 is about 276.2179542825.

The spelling of 21074424 in words is "twenty-one million, seventy-four thousand, four hundred twenty-four".