21534648 has 64 divisors (see below), whose sum is σ = 58268160. Its totient is φ = 6606336.

The previous prime is 21534577. The next prime is 21534659. The reversal of 21534648 is 84643512.

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, 18615 + ... + 19737.

It is an arithmetic number, because the mean of its divisors is an integer number (910440).

Almost surely, 2^21534648 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 21534648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29134080).

21534648 is an abundant number, since it is smaller than the sum of its proper divisors (36733512).

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

21534648 is a wasteful number, since it uses less digits than its factorization.

21534648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1196 (or 1192 counting only the distinct ones).

The product of its digits is 23040, while the sum is 33.

The square root of 21534648 is about 4640.5439336354. The cubic root of 21534648 is about 278.2141785818.

The spelling of 21534648 in words is "twenty-one million, five hundred thirty-four thousand, six hundred forty-eight".