139609209 has 8 divisors (see below), whose sum is σ = 186200320. Its totient is φ = 93045456.

The previous prime is 139609201. The next prime is 139609229. The reversal of 139609209 is 902906931.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 139609209 - 2³ = 139609201 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (139609201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15447 + ... + 22755.

It is an arithmetic number, because the mean of its divisors is an integer number (23275040).

Almost surely, 2^139609209 is an apocalyptic number.

It is an amenable number.

139609209 is a deficient number, since it is larger than the sum of its proper divisors (46591111).

139609209 is an equidigital number, since it uses as much as digits as its factorization.

139609209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13679.

The product of its (nonzero) digits is 26244, while the sum is 39.

The square root of 139609209 is about 11815.6340921679. The cubic root of 139609209 is about 518.7658218622.

The spelling of 139609209 in words is "one hundred thirty-nine million, six hundred nine thousand, two hundred nine".