139778309 has 4 divisors (see below), whose sum is σ = 152485440. Its totient is φ = 127071180.

The previous prime is 139778299. The next prime is 139778323. The reversal of 139778309 is 903877931.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 139778309 - 2⁴ = 139778293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139778399) 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 3 ways as a sum of consecutive naturals, for example, 6353549 + ... + 6353570.

It is an arithmetic number, because the mean of its divisors is an integer number (38121360).

Almost surely, 2^139778309 is an apocalyptic number.

It is an amenable number.

139778309 is a deficient number, since it is larger than the sum of its proper divisors (12707131).

139778309 is a wasteful number, since it uses less digits than its factorization.

139778309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12707130.

The product of its (nonzero) digits is 285768, while the sum is 47.

The square root of 139778309 is about 11822.7877000308. The cubic root of 139778309 is about 518.9751870060.

The spelling of 139778309 in words is "one hundred thirty-nine million, seven hundred seventy-eight thousand, three hundred nine".