21075924 has 48 divisors (see below), whose sum is σ = 51649920. Its totient is φ = 6679680.

The previous prime is 21075919. The next prime is 21075931. The reversal of 21075924 is 42957012.

It is a junction number, because it is equal to n+sod(n) for n = 21075891 and 21075900.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24282 + ... + 25134.

It is an arithmetic number, because the mean of its divisors is an integer number (1076040).

Almost surely, 2^21075924 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21075924, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25824960).

21075924 is an abundant number, since it is smaller than the sum of its proper divisors (30573996).

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

21075924 is a wasteful number, since it uses less digits than its factorization.

21075924 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 960 (or 958 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 21075924 is about 4590.8522084685. The cubic root of 21075924 is about 276.2245075198.

The spelling of 21075924 in words is "twenty-one million, seventy-five thousand, nine hundred twenty-four".