21165030 has 64 divisors (see below), whose sum is σ = 57784320. Its totient is φ = 5509728.

The previous prime is 21165019. The next prime is 21165047. The reversal of 21165030 is 3056112.

21165030 is a `hidden beast` number, since 2 + 11 + 650 + 3 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21164994 and 21165012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10699 + ... + 12521.

It is an arithmetic number, because the mean of its divisors is an integer number (902880).

Almost surely, 2^21165030 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21165030, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28892160).

21165030 is an abundant number, since it is smaller than the sum of its proper divisors (36619290).

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

21165030 is a wasteful number, since it uses less digits than its factorization.

21165030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1882 (or 1876 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 21165030 is about 4600.5467066426. The cubic root of 21165030 is about 276.6132394696.

The spelling of 21165030 in words is "twenty-one million, one hundred sixty-five thousand, thirty".