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15616 = 2861

15616 has 18 divisors (see below), whose sum is σ = 31682. Its totient is φ = 7680.

The previous prime is 15607. The next prime is 15619. The reversal of 15616 is 61651.

It can be written as a sum of positive squares in only one way, i.e., 9216 + 6400 = 96^2 + 80^2 .

It is a nialpdrome in base 4 and base 5.

It is a junction number, because it is equal to n+sod(n) for n = 15593 and 15602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 226 + ... + 286.

215616 is an apocalyptic number.

15616 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15841).

15616 is an abundant number, since it is smaller than the sum of its proper divisors (16066).

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

15616 is an frugal number, since it uses more digits than its factorization.

15616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77 (or 63 counting only the distinct ones).

The product of its digits is 180, while the sum is 19.

The square root of 15616 is about 124.9639948145. The cubic root of 15616 is about 24.9951990781.

The spelling of 15616 in words is "fifteen thousand, six hundred sixteen".

Divisors: 1 2 4 8 16 32 61 64 122 128 244 256 488 976 1952 3904 7808 15616