21118312 has 8 divisors (see below), whose sum is σ = 39596850. Its totient is φ = 10559152.

The previous prime is 21118303. The next prime is 21118337. The reversal of 21118312 is 21381112.

It can be written as a sum of positive squares in only one way, i.e., 19061956 + 2056356 = 4366^2 + 1434^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21118312.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1319887 + ... + 1319902.

Almost surely, 2^21118312 is an apocalyptic number.

It is an amenable number.

21118312 is a deficient number, since it is larger than the sum of its proper divisors (18478538).

21118312 is a wasteful number, since it uses less digits than its factorization.

21118312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2639795 (or 2639791 counting only the distinct ones).

The product of its digits is 96, while the sum is 19.

The square root of 21118312 is about 4595.4664616337. The cubic root of 21118312 is about 276.4095648664.

Adding to 21118312 its reverse (21381112), we get a palindrome (42499424).

The spelling of 21118312 in words is "twenty-one million, one hundred eighteen thousand, three hundred twelve".