21330612 has 18 divisors (see below), whose sum is σ = 53919138. Its totient is φ = 7110192.

The previous prime is 21330607. The next prime is 21330629. The reversal of 21330612 is 21603312.

21330612 is a `hidden beast` number, since 21 + 3 + 30 + 612 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21288996 + 41616 = 4614^2 + 204^2 .

It is a tau number, because it is divible by the number of its divisors (18).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 296223 + ... + 296294.

Almost surely, 2^21330612 is an apocalyptic number.

It is an amenable number.

21330612 is an abundant number, since it is smaller than the sum of its proper divisors (32588526).

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

21330612 is a wasteful number, since it uses less digits than its factorization.

21330612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 592527 (or 592522 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21330612 is about 4618.5075511468. The cubic root of 21330612 is about 277.3327163191.

Adding to 21330612 its reverse (21603312), we get a palindrome (42933924).

The spelling of 21330612 in words is "twenty-one million, three hundred thirty thousand, six hundred twelve".