16139665 has 4 divisors (see below), whose sum is σ = 19367604. Its totient is φ = 12911728.

The previous prime is 16139611. The next prime is 16139671. The reversal of 16139665 is 56693161.

16139665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56693161 = 7 ⋅8099023.

It can be written as a sum of positive squares in 2 ways, for example, as 2663424 + 13476241 = 1632^2 + 3671^2 .

It is a cyclic number.

It is not a de Polignac number, because 16139665 - 2⁹ = 16139153 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1613962 + ... + 1613971.

It is an arithmetic number, because the mean of its divisors is an integer number (4841901).

Almost surely, 2^16139665 is an apocalyptic number.

It is an amenable number.

16139665 is a deficient number, since it is larger than the sum of its proper divisors (3227939).

16139665 is an equidigital number, since it uses as much as digits as its factorization.

16139665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3227938.

The product of its digits is 29160, while the sum is 37.

The square root of 16139665 is about 4017.4201921133. The cubic root of 16139665 is about 252.7152822016.

The spelling of 16139665 in words is "sixteen million, one hundred thirty-nine thousand, six hundred sixty-five".