21165066 has 48 divisors (see below), whose sum is σ = 49795200. Its totient is φ = 6458400.

The previous prime is 21165047. The next prime is 21165077. The reversal of 21165066 is 66056112.

It is a happy number.

21165066 is a `hidden beast` number, since 2 + 1 + 1 + 650 + 6 + 6 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35035 + ... + 35633.

It is an arithmetic number, because the mean of its divisors is an integer number (1037400).

Almost surely, 2^21165066 is an apocalyptic number.

21165066 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21165066, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24897600).

21165066 is an abundant number, since it is smaller than the sum of its proper divisors (28630134).

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

21165066 is a wasteful number, since it uses less digits than its factorization.

21165066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 771 (or 768 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 21165066 is about 4600.5506192194. The cubic root of 21165066 is about 276.6133963018.

The spelling of 21165066 in words is "twenty-one million, one hundred sixty-five thousand, sixty-six".