21132648 has 72 divisors (see below), whose sum is σ = 59445750. Its totient is φ = 6781824.

The previous prime is 21132623. The next prime is 21132659. The reversal of 21132648 is 84623112.

21132648 is a `hidden beast` number, since 2 + 1 + 13 + 2 + 648 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 19873764 + 1258884 = 4458^2 + 1122^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×21132648² = 893177622983808, which contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 60378 + ... + 60726.

Almost surely, 2^21132648 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 21132648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29722875).

21132648 is an abundant number, since it is smaller than the sum of its proper divisors (38313102).

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

21132648 is a wasteful number, since it uses less digits than its factorization.

21132648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419 (or 383 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21132648 is about 4597.0259951408. The cubic root of 21132648 is about 276.4720968717.

It can be divided in two parts, 2113 and 2648, that added together give a square (4761 = 69²).

The spelling of 21132648 in words is "twenty-one million, one hundred thirty-two thousand, six hundred forty-eight".