139665121 has 8 divisors (see below), whose sum is σ = 144198144. Its totient is φ = 135172080.

The previous prime is 139665109. The next prime is 139665151. The reversal of 139665121 is 121566931.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 139665121 - 2⁵ = 139665089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139665151) 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 7 ways as a sum of consecutive naturals, for example, 2815 + ... + 16948.

It is an arithmetic number, because the mean of its divisors is an integer number (18024768).

Almost surely, 2^139665121 is an apocalyptic number.

It is an amenable number.

139665121 is a deficient number, since it is larger than the sum of its proper divisors (4533023).

139665121 is a wasteful number, since it uses less digits than its factorization.

139665121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19991.

The product of its digits is 9720, while the sum is 34.

The square root of 139665121 is about 11817.9998730750. Note that the first 3 decimals coincide. The cubic root of 139665121 is about 518.8350660131.

The spelling of 139665121 in words is "one hundred thirty-nine million, six hundred sixty-five thousand, one hundred twenty-one".