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21245641 = 33896269
BaseRepresentation
bin101000100001…
…0111011001001
31110222101112121
41101002323021
520414330031
62035211241
7345404434
oct121027311
943871477
1021245641
1110aa118a
127146b21
13452b3b1
142b7081b
151cea011
hex1442ec9

21245641 has 4 divisors (see below), whose sum is σ = 21255300. Its totient is φ = 21235984.

The previous prime is 21245617. The next prime is 21245669. The reversal of 21245641 is 14654212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 15015625 + 6230016 = 3875^2 + 2496^2 .

It is a cyclic number.

It is not a de Polignac number, because 21245641 - 27 = 21245513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21245941) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 255 + ... + 6523.

It is an arithmetic number, because the mean of its divisors is an integer number (5313825).

Almost surely, 221245641 is an apocalyptic number.

It is an amenable number.

21245641 is a deficient number, since it is larger than the sum of its proper divisors (9659).

21245641 is an equidigital number, since it uses as much as digits as its factorization.

21245641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9658.

The product of its digits is 1920, while the sum is 25.

The square root of 21245641 is about 4609.2994044648. The cubic root of 21245641 is about 276.9639724286.

Adding to 21245641 its reverse (14654212), we get a palindrome (35899853).

The spelling of 21245641 in words is "twenty-one million, two hundred forty-five thousand, six hundred forty-one".

Divisors: 1 3389 6269 21245641