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645561 = 32710247
BaseRepresentation
bin10011101100110111001
31012210112200
42131212321
5131124221
621500413
75326050
oct2354671
91183480
10645561
11401024
12271709
13197ab7
1412b397
15cb426
hex9d9b9

645561 has 12 divisors (see below), whose sum is σ = 1065792. Its totient is φ = 368856.

The previous prime is 645529. The next prime is 645571. The reversal of 645561 is 165546.

It is a happy number.

645561 is nontrivially palindromic in base 2.

It is not a de Polignac number, because 645561 - 25 = 645529 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (645521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5061 + ... + 5186.

It is an arithmetic number, because the mean of its divisors is an integer number (88816).

2645561 is an apocalyptic number.

It is an amenable number.

645561 is a deficient number, since it is larger than the sum of its proper divisors (420231).

645561 is a wasteful number, since it uses less digits than its factorization.

645561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10260 (or 10257 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

The square root of 645561 is about 803.4681076434. The cubic root of 645561 is about 86.4262683759.

It can be divided in two parts, 64 and 5561, that added together give a square (5625 = 752).

The spelling of 645561 in words is "six hundred forty-five thousand, five hundred sixty-one".

Divisors: 1 3 7 9 21 63 10247 30741 71729 92223 215187 645561