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664561 is a prime number
BaseRepresentation
bin10100010001111110001
31020202121101
42202033301
5132231221
622124401
75435332
oct2421761
91222541
10664561
11414327
12280701
131a3641
14134289
15d1d91
hexa23f1

664561 has 2 divisors, whose sum is σ = 664562. Its totient is φ = 664560.

The previous prime is 664549. The next prime is 664571. The reversal of 664561 is 165466.

664561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 571536 + 93025 = 756^2 + 305^2 .

It is a cyclic number.

It is not a de Polignac number, because 664561 - 25 = 664529 is a prime.

It is not a weakly prime, because it can be changed into another prime (664511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332280 + 332281.

It is an arithmetic number, because the mean of its divisors is an integer number (332281).

2664561 is an apocalyptic number.

It is an amenable number.

664561 is a deficient number, since it is larger than the sum of its proper divisors (1).

664561 is an equidigital number, since it uses as much as digits as its factorization.

664561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 28.

The square root of 664561 is about 815.2061089074. The cubic root of 664561 is about 87.2659760074.

It can be divided in two parts, 664 and 561, that added together give a triangular number (1225 = T49).

The spelling of 664561 in words is "six hundred sixty-four thousand, five hundred sixty-one".