21278512 has 10 divisors (see below), whose sum is σ = 41227148. Its totient is φ = 10639248.

The previous prime is 21278501. The next prime is 21278557. The reversal of 21278512 is 21587212.

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, 664938 + ... + 664969.

Almost surely, 2^21278512 is an apocalyptic number.

It is an amenable number.

21278512 is a deficient number, since it is larger than the sum of its proper divisors (19948636).

21278512 is a wasteful number, since it uses less digits than its factorization.

21278512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1329915 (or 1329909 counting only the distinct ones).

The product of its digits is 2240, while the sum is 28.

The square root of 21278512 is about 4612.8637525945. The cubic root of 21278512 is about 277.1067372672.

The spelling of 21278512 in words is "twenty-one million, two hundred seventy-eight thousand, five hundred twelve".