21599648 has 48 divisors (see below), whose sum is σ = 48936384. Its totient is φ = 9192960.

The previous prime is 21599647. The next prime is 21599651. The reversal of 21599648 is 84699512.

It is a junction number, because it is equal to n+sod(n) for n = 21599599 and 21599608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21599647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47036 + ... + 47492.

It is an arithmetic number, because the mean of its divisors is an integer number (1019508).

Almost surely, 2^21599648 is an apocalyptic number.

21599648 is a gapful number since it is divisible by the number (28) 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 21599648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24468192).

21599648 is an abundant number, since it is smaller than the sum of its proper divisors (27336736).

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

21599648 is a wasteful number, since it uses less digits than its factorization.

21599648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685 (or 677 counting only the distinct ones).

The product of its digits is 155520, while the sum is 44.

The square root of 21599648 is about 4647.5421461241. The cubic root of 21599648 is about 278.4938171944.

The spelling of 21599648 in words is "twenty-one million, five hundred ninety-nine thousand, six hundred forty-eight".