21402648 has 96 divisors (see below), whose sum is σ = 61501440. Its totient is φ = 6713280.

The previous prime is 21402637. The next prime is 21402653. The reversal of 21402648 is 84620412.

21402648 is a `hidden beast` number, since 2 + 14 + 0 + 2 + 648 = 666.

It is a super-4 number, since 4×21402648⁴ (a number of 30 digits) contains 4444 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 95865 + ... + 96087.

It is an arithmetic number, because the mean of its divisors is an integer number (640640).

Almost surely, 2^21402648 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 21402648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30750720).

21402648 is an abundant number, since it is smaller than the sum of its proper divisors (40098792).

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

21402648 is a wasteful number, since it uses less digits than its factorization.

21402648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309 (or 302 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 21402648 is about 4626.2996011932. The cubic root of 21402648 is about 277.6445606669.

The spelling of 21402648 in words is "twenty-one million, four hundred two thousand, six hundred forty-eight".