139905439 has 4 divisors (see below), whose sum is σ = 139946400. Its totient is φ = 139864480.

The previous prime is 139905433. The next prime is 139905463. The reversal of 139905439 is 934509931.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 934509931 = 97 ⋅9634123.

It is a cyclic number.

It is not a de Polignac number, because 139905439 - 2³ = 139905431 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 139905395 and 139905404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139905431) 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, 14839 + ... + 22360.

It is an arithmetic number, because the mean of its divisors is an integer number (34986600).

Almost surely, 2^139905439 is an apocalyptic number.

139905439 is a deficient number, since it is larger than the sum of its proper divisors (40961).

139905439 is an equidigital number, since it uses as much as digits as its factorization.

139905439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40960.

The product of its (nonzero) digits is 131220, while the sum is 43.

The square root of 139905439 is about 11828.1629596485. The cubic root of 139905439 is about 519.1324773222.

The spelling of 139905439 in words is "one hundred thirty-nine million, nine hundred five thousand, four hundred thirty-nine".