139878161 has 4 divisors (see below), whose sum is σ = 140422692. Its totient is φ = 139333632.

The previous prime is 139878139. The next prime is 139878163. The reversal of 139878161 is 161878931.

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

It can be written as a sum of positive squares in 2 ways, for example, as 73960000 + 65918161 = 8600^2 + 8119^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139878161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139878163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 271880 + ... + 272393.

It is an arithmetic number, because the mean of its divisors is an integer number (35105673).

Almost surely, 2^139878161 is an apocalyptic number.

It is an amenable number.

139878161 is a deficient number, since it is larger than the sum of its proper divisors (544531).

139878161 is an equidigital number, since it uses as much as digits as its factorization.

139878161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544530.

The product of its digits is 72576, while the sum is 44.

The square root of 139878161 is about 11827.0098080622. The cubic root of 139878161 is about 519.0987359222.

The spelling of 139878161 in words is "one hundred thirty-nine million, eight hundred seventy-eight thousand, one hundred sixty-one".