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21640045 = 57618287
BaseRepresentation
bin101001010001…
…1001101101101
31111201102120011
41102203031231
521014440140
62051453221
7351636340
oct122431555
944642504
1021640045
1111240539
1272b7211
134638a7b
142c34457
151d76cea
hex14a336d

21640045 has 8 divisors (see below), whose sum is σ = 29677824. Its totient is φ = 14838864.

The previous prime is 21640039. The next prime is 21640049. The reversal of 21640045 is 54004612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21640045 - 25 = 21640013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21639998 and 21640025.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21640049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 309109 + ... + 309178.

It is an arithmetic number, because the mean of its divisors is an integer number (3709728).

Almost surely, 221640045 is an apocalyptic number.

It is an amenable number.

21640045 is a deficient number, since it is larger than the sum of its proper divisors (8037779).

21640045 is an equidigital number, since it uses as much as digits as its factorization.

21640045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 618299.

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 21640045 is about 4651.8861765955. The cubic root of 21640045 is about 278.6673278666.

Adding to 21640045 its reverse (54004612), we get a palindrome (75644657).

The spelling of 21640045 in words is "twenty-one million, six hundred forty thousand, forty-five".

Divisors: 1 5 7 35 618287 3091435 4328009 21640045