16656660 has 144 divisors (see below), whose sum is σ = 54027792. Its totient is φ = 4147200.

The previous prime is 16656649. The next prime is 16656677. The reversal of 16656660 is 6665661.

16656660 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 2862864 + 13793796 = 1692^2 + 3714^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 273030 + ... + 273090.

It is an arithmetic number, because the mean of its divisors is an integer number (375193).

Almost surely, 2^16656660 is an apocalyptic number.

16656660 is a gapful number since it is divisible by the number (10) 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 16656660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27013896).

16656660 is an abundant number, since it is smaller than the sum of its proper divisors (37371132).

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

16656660 is a wasteful number, since it uses less digits than its factorization.

16656660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 16656660 is about 4081.2571592587. The cubic root of 16656660 is about 255.3853458763.

Subtracting from 16656660 its reverse (6665661), we obtain a palindrome (9990999).

It can be divided in two parts, 1665 and 6660, that multiplied together give a square (11088900 = 3330²).

The spelling of 16656660 in words is "sixteen million, six hundred fifty-six thousand, six hundred sixty".