15666228 has 54 divisors (see below), whose sum is σ = 40666626. Its totient is φ = 5085024.

The previous prime is 15666227. The next prime is 15666229. The reversal of 15666228 is 82266651.

15666228 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (15666227) and next prime (15666229).

It can be written as a sum of positive squares in only one way, i.e., 15586704 + 79524 = 3948^2 + 282^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 15666192 and 15666201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15666227) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 79426 + ... + 79622.

Almost surely, 2^15666228 is an apocalyptic number.

15666228 is a gapful number since it is divisible by the number (18) 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 15666228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20333313).

15666228 is an abundant number, since it is smaller than the sum of its proper divisors (25000398).

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

15666228 is a wasteful number, since it uses less digits than its factorization.

15666228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301 (or 249 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 15666228 is about 3958.0586150283. The cubic root of 15666228 is about 250.2196895561.

The spelling of 15666228 in words is "fifteen million, six hundred sixty-six thousand, two hundred twenty-eight".