21339648 has 120 divisors (see below), whose sum is σ = 67346136. Its totient is φ = 6451200.

The previous prime is 21339629. The next prime is 21339649. The reversal of 21339648 is 84693312.

21339648 is a `hidden beast` number, since 2 + 1 + 3 + 3 + 9 + 648 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21339649) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 50478 + ... + 50898.

Almost surely, 2^21339648 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 21339648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33673068).

21339648 is an abundant number, since it is smaller than the sum of its proper divisors (46006488).

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

21339648 is a wasteful number, since it uses less digits than its factorization.

21339648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456 (or 437 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21339648 is about 4619.4856856581. The cubic root of 21339648 is about 277.3718716990.

It can be divided in two parts, 213396 and 48, that added together give a square (213444 = 462²).

The spelling of 21339648 in words is "twenty-one million, three hundred thirty-nine thousand, six hundred forty-eight".