21230312 has 8 divisors (see below), whose sum is σ = 39806850. Its totient is φ = 10615152.

The previous prime is 21230309. The next prime is 21230329. The reversal of 21230312 is 21303212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21031396 + 198916 = 4586^2 + 446^2 .

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

It is a super-2 number, since 2×21230312² = 901452295234688, which contains 22 as substring.

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 as a sum of consecutive naturals, namely, 1326887 + ... + 1326902.

Almost surely, 2^21230312 is an apocalyptic number.

It is an amenable number.

21230312 is a deficient number, since it is larger than the sum of its proper divisors (18576538).

21230312 is a wasteful number, since it uses less digits than its factorization.

21230312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2653795 (or 2653791 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21230312 is about 4607.6362703668. The cubic root of 21230312 is about 276.8973453932.

Adding to 21230312 its reverse (21303212), we get a palindrome (42533524).

Subtracting 21230312 from its reverse (21303212), we obtain a square (72900 = 270²).

The spelling of 21230312 in words is "twenty-one million, two hundred thirty thousand, three hundred twelve".