21059424 has 72 divisors (see below), whose sum is σ = 60678072. Its totient is φ = 6927360.

The previous prime is 21059417. The next prime is 21059449. The reversal of 21059424 is 42495012.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23464 + ... + 24344.

It is an arithmetic number, because the mean of its divisors is an integer number (842751).

Almost surely, 2^21059424 is an apocalyptic number.

21059424 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 21059424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30339036).

21059424 is an abundant number, since it is smaller than the sum of its proper divisors (39618648).

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

21059424 is a wasteful number, since it uses less digits than its factorization.

21059424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 980 (or 969 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 21059424 is about 4589.0548046411. The cubic root of 21059424 is about 276.1524048008.

The spelling of 21059424 in words is "twenty-one million, fifty-nine thousand, four hundred twenty-four".