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209815225 = 5228972
BaseRepresentation
bin11001000000110…
…00011010111001
3112121210201101021
430200120122321
5412203041400
632453022441
75125254124
oct1440303271
9477721337
10209815225
11a8487314
125a324a21
1334612a29
141dc193bb
151364771a
hexc8186b9

209815225 has 9 divisors (see below), whose sum is σ = 260260717. Its totient is φ = 167794240.

The previous prime is 209815211. The next prime is 209815237. The reversal of 209815225 is 522518902.

It is a happy number.

The square root of 209815225 is 14485.

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

It can be written as a sum of positive squares in 4 ways, for example, as 63792169 + 146023056 = 7987^2 + 12084^2 .

It is not a de Polignac number, because 209815225 - 29 = 209814713 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 70977 + ... + 73873.

Almost surely, 2209815225 is an apocalyptic number.

209815225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

209815225 is the 14485-th square number.

209815225 is the 7243-rd centered octagonal number.

It is an amenable number.

209815225 is a deficient number, since it is larger than the sum of its proper divisors (50445492).

209815225 is an frugal number, since it uses more digits than its factorization.

209815225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5804 (or 2902 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 34.

The cubic root of 209815225 is about 594.2178126640.

Multiplying 209815225 by its product of nonzero digits (14400), we get a square (3021339240000 = 17382002).

The spelling of 209815225 in words is "two hundred nine million, eight hundred fifteen thousand, two hundred twenty-five".

Divisors: 1 5 25 2897 14485 72425 8392609 41963045 209815225