21043012 has 12 divisors (see below), whose sum is σ = 36858556. Its totient is φ = 10512000.

The previous prime is 21043007. The next prime is 21043019. The reversal of 21043012 is 21034012.

It can be written as a sum of positive squares in 2 ways, for example, as 4769856 + 16273156 = 2184^2 + 4034^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21042983 and 21043001.

It is not an unprimeable number, because it can be changed into a prime (21043019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5512 + ... + 8512.

Almost surely, 2^21043012 is an apocalyptic number.

It is an amenable number.

21043012 is a deficient number, since it is larger than the sum of its proper divisors (15815544).

21043012 is a wasteful number, since it uses less digits than its factorization.

21043012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4758 (or 4756 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21043012 is about 4587.2662883247. The cubic root of 21043012 is about 276.0806492592.

Adding to 21043012 its reverse (21034012), we get a palindrome (42077024).

The spelling of 21043012 in words is "twenty-one million, forty-three thousand, twelve".