15646 has 4 divisors (see below), whose sum is σ = 23472. Its totient is φ = 7822.

The previous prime is 15643. The next prime is 15647. The reversal of 15646 is 64651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 64651 = 17 ⋅3803.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3910 + ... + 3913.

It is an arithmetic number, because the mean of its divisors is an integer number (5868).

2¹⁵⁶⁴⁶ is an apocalyptic number.

15646 is a deficient number, since it is larger than the sum of its proper divisors (7826).

15646 is an equidigital number, since it uses as much as digits as its factorization.

15646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7825.

The product of its digits is 720, while the sum is 22.

The square root of 15646 is about 125.0839717950. The cubic root of 15646 is about 25.0111949861.

It can be divided in two parts, 156 and 46, that added together give a palindrome (202).

The spelling of 15646 in words is "fifteen thousand, six hundred forty-six".