209390231 has 4 divisors (see below), whose sum is σ = 209653752. Its totient is φ = 209126712.

The previous prime is 209390221. The next prime is 209390249. The reversal of 209390231 is 132093902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 209390231 - 2¹⁰ = 209389207 is a prime.

It is a super-2 number, since 2×209390231² = 87688537676466722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 209390194 and 209390203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209390221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130565 + ... + 132158.

It is an arithmetic number, because the mean of its divisors is an integer number (52413438).

Almost surely, 2^209390231 is an apocalyptic number.

209390231 is a deficient number, since it is larger than the sum of its proper divisors (263521).

209390231 is an equidigital number, since it uses as much as digits as its factorization.

209390231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263520.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 209390231 is about 14470.3224221162. The cubic root of 209390231 is about 593.8163328883.

The spelling of 209390231 in words is "two hundred nine million, three hundred ninety thousand, two hundred thirty-one".