21063744 has 168 divisors, whose sum is σ = 67955160. Its totient is φ = 6193152.

The previous prime is 21063743. The next prime is 21063751. The reversal of 21063744 is 44736012.

21063744 is a `hidden beast` number, since 21 + 0 + 637 + 4 + 4 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 705600 + 20358144 = 840^2 + 4512^2 .

It is a super-2 number, since 2×21063744² = 887362622595072, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21063743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 217104 + ... + 217200.

It is an arithmetic number, because the mean of its divisors is an integer number (404495).

Almost surely, 2^21063744 is an apocalyptic number.

21063744 is a gapful number since it is divisible by the number (24) 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 21063744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33977580).

21063744 is an abundant number, since it is smaller than the sum of its proper divisors (46891416).

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

21063744 is a wasteful number, since it uses less digits than its factorization.

21063744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157 (or 144 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 21063744 is about 4589.5254656664. The cubic root of 21063744 is about 276.1712862420.

Adding to 21063744 its reverse (44736012), we get a palindrome (65799756).

It can be divided in two parts, 2106374 and 4, that added together give a triangular number (2106378 = T₂₀₅₂).

The spelling of 21063744 in words is "twenty-one million, sixty-three thousand, seven hundred forty-four".