209081231 has 2 divisors, whose sum is σ = 209081232. Its totient is φ = 209081230.

The previous prime is 209081227. The next prime is 209081273. The reversal of 209081231 is 132180902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 209081231 - 2² = 209081227 is a prime.

It is a super-2 number, since 2×209081231² = 87429922312950722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 209081231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209081281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104540615 + 104540616.

It is an arithmetic number, because the mean of its divisors is an integer number (104540616).

Almost surely, 2^209081231 is an apocalyptic number.

209081231 is a deficient number, since it is larger than the sum of its proper divisors (1).

209081231 is an equidigital number, since it uses as much as digits as its factorization.

209081231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 209081231 is about 14459.6414547526. The cubic root of 209081231 is about 593.5240881494.

The spelling of 209081231 in words is "two hundred nine million, eighty-one thousand, two hundred thirty-one".