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690561 = 322772
BaseRepresentation
bin10101000100110000001
31022002021100
42220212001
5134044221
622445013
75604204
oct2504601
91262240
10690561
11431913
12293769
131b2421
1413d93b
15d9926
hexa8981

690561 has 9 divisors (see below), whose sum is σ = 1001091. Its totient is φ = 458712.

The previous prime is 690553. The next prime is 690583. The reversal of 690561 is 165096.

The square root of 690561 is 831.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 119025 + 571536 = 345^2 + 756^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 690561 - 23 = 690553 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (690511) 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 8 ways as a sum of consecutive naturals, for example, 2355 + ... + 2631.

2690561 is an apocalyptic number.

690561 is the 831-st square number.

690561 is the 416-th centered octagonal number.

It is an amenable number.

690561 is a deficient number, since it is larger than the sum of its proper divisors (310530).

690561 is an equidigital number, since it uses as much as digits as its factorization.

690561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 560 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The cubic root of 690561 is about 88.3895010838.

The spelling of 690561 in words is "six hundred ninety thousand, five hundred sixty-one".

Divisors: 1 3 9 277 831 2493 76729 230187 690561