209389131 has 20 divisors (see below), whose sum is σ = 357476592. Its totient is φ = 119650608.

The previous prime is 209389129. The next prime is 209389151. The reversal of 209389131 is 131983902.

209389131 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 209389131 - 2¹ = 209389129 is a prime.

It is a super-2 number, since 2×209389131² = 87687616361870322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (209389121) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 184080 + ... + 185213.

Almost surely, 2^209389131 is an apocalyptic number.

209389131 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

209389131 is a deficient number, since it is larger than the sum of its proper divisors (148087461).

209389131 is an equidigital number, since it uses as much as digits as its factorization.

209389131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369312 (or 369303 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 209389131 is about 14470.2844132380. The cubic root of 209389131 is about 593.8152930449.

The spelling of 209389131 in words is "two hundred nine million, three hundred eighty-nine thousand, one hundred thirty-one".