15664 has 20 divisors (see below), whose sum is σ = 33480. Its totient is φ = 7040.

The previous prime is 15661. The next prime is 15667. The reversal of 15664 is 46651.

15664 is nontrivially palindromic in base 15.

15664 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

15664 is an esthetic number in base 9, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (15661) and next prime (15667).

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (15661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132 + ... + 220.

It is an arithmetic number, because the mean of its divisors is an integer number (1674).

2¹⁵⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16740).

15664 is an abundant number, since it is smaller than the sum of its proper divisors (17816).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15664 is a wasteful number, since it uses less digits than its factorization.

15664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108 (or 102 counting only the distinct ones).

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

The square root of 15664 is about 125.1559027773. The cubic root of 15664 is about 25.0207827184.

Adding to 15664 its product of digits (720), we get a 14-th power (16384 = 2¹⁴).

It can be divided in two parts, 1 and 5664, that added together give a palindrome (5665).

The spelling of 15664 in words is "fifteen thousand, six hundred sixty-four".