209681312 has 12 divisors (see below), whose sum is σ = 412810146. Its totient is φ = 104840640.

The previous prime is 209681291. The next prime is 209681341. The reversal of 209681312 is 213186902.

It can be written as a sum of positive squares in only one way, i.e., 209554576 + 126736 = 14476^2 + 356^2 .

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 6552541 = 209681312 / (2 + 0 + 9 + 6 + 8 + 1 + 3 + 1 + 2).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3276239 + ... + 3276302.

Almost surely, 2^209681312 is an apocalyptic number.

It is an amenable number.

209681312 is a deficient number, since it is larger than the sum of its proper divisors (203128834).

209681312 is an equidigital number, since it uses as much as digits as its factorization.

209681312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6552551 (or 6552543 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 209681312 is about 14480.3767906778. The cubic root of 209681312 is about 594.0913673993.

The spelling of 209681312 in words is "two hundred nine million, six hundred eighty-one thousand, three hundred twelve".