21040312 has 32 divisors (see below), whose sum is σ = 41310000. Its totient is φ = 10033408.

The previous prime is 21040297. The next prime is 21040387. The reversal of 21040312 is 21304012.

It is a junction number, because it is equal to n+sod(n) for n = 21040292 and 21040301.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20139 + ... + 21157.

Almost surely, 2^21040312 is an apocalyptic number.

It is an amenable number.

21040312 is a deficient number, since it is larger than the sum of its proper divisors (20269688).

21040312 is a wasteful number, since it uses less digits than its factorization.

21040312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1143 (or 1139 counting only the distinct ones).

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

The square root of 21040312 is about 4586.9719859620. The cubic root of 21040312 is about 276.0688409111.

Adding to 21040312 its reverse (21304012), we get a palindrome (42344324).

The spelling of 21040312 in words is "twenty-one million, forty thousand, three hundred twelve".