209239427 has 2 divisors, whose sum is σ = 209239428. Its totient is φ = 209239426.

The previous prime is 209239409. The next prime is 209239447. The reversal of 209239427 is 724932902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 209239427 - 2⁶ = 209239363 is a prime.

It is a super-2 number, since 2×209239427² = 87562275622576658, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (209239447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104619713 + 104619714.

It is an arithmetic number, because the mean of its divisors is an integer number (104619714).

Almost surely, 2^209239427 is an apocalyptic number.

209239427 is a deficient number, since it is larger than the sum of its proper divisors (1).

209239427 is an equidigital number, since it uses as much as digits as its factorization.

209239427 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54432, while the sum is 38.

The square root of 209239427 is about 14465.1106805306. The cubic root of 209239427 is about 593.6737420511.

The spelling of 209239427 in words is "two hundred nine million, two hundred thirty-nine thousand, four hundred twenty-seven".