139905779 has 4 divisors (see below), whose sum is σ = 150667776. Its totient is φ = 129143784.

The previous prime is 139905749. The next prime is 139905809. The reversal of 139905779 is 977509931.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (139905749) and next prime (139905809).

It is a cyclic number.

It is not a de Polignac number, because 139905779 - 2²⁰ = 138857203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139905739) 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, 5380979 + ... + 5381004.

It is an arithmetic number, because the mean of its divisors is an integer number (37666944).

Almost surely, 2^139905779 is an apocalyptic number.

139905779 is a deficient number, since it is larger than the sum of its proper divisors (10761997).

139905779 is a wasteful number, since it uses less digits than its factorization.

139905779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10761996.

The product of its (nonzero) digits is 535815, while the sum is 50.

The square root of 139905779 is about 11828.1773321167. The cubic root of 139905779 is about 519.1328978560.

The spelling of 139905779 in words is "one hundred thirty-nine million, nine hundred five thousand, seven hundred seventy-nine".