15665216 has 56 divisors (see below), whose sum is σ = 36088320. Its totient is φ = 6607872.

The previous prime is 15665213. The next prime is 15665219. The reversal of 15665216 is 61256651.

It is an interprime number because it is at equal distance from previous prime (15665213) and next prime (15665219).

It is a tau number, because it is divible by the number of its divisors (56).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15665213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32465 + ... + 32943.

Almost surely, 2^15665216 is an apocalyptic number.

15665216 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 15665216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18044160).

15665216 is an abundant number, since it is smaller than the sum of its proper divisors (20423104).

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

15665216 is an equidigital number, since it uses as much as digits as its factorization.

15665216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 571 (or 561 counting only the distinct ones).

The product of its digits is 10800, while the sum is 32.

The square root of 15665216 is about 3957.9307725123. The cubic root of 15665216 is about 250.2143015802.

The spelling of 15665216 in words is "fifteen million, six hundred sixty-five thousand, two hundred sixteen".