139609 has 2 divisors, whose sum is σ = 139610. Its totient is φ = 139608.

The previous prime is 139597. The next prime is 139619. The reversal of 139609 is 906931.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138384 + 1225 = 372^2 + 35^2 .

It is an emirp because it is prime and its reverse (906931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 139609 - 2¹⁷ = 8537 is a prime.

It is not a weakly prime, because it can be changed into another prime (139619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69804 + 69805.

It is an arithmetic number, because the mean of its divisors is an integer number (69805).

2¹³⁹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

139609 is a deficient number, since it is larger than the sum of its proper divisors (1).

139609 is an equidigital number, since it uses as much as digits as its factorization.

139609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 139609 is about 373.6428776251. The cubic root of 139609 is about 51.8765562992.

The spelling of 139609 in words is "one hundred thirty-nine thousand, six hundred nine".