21363728 has 10 divisors (see below), whose sum is σ = 41392254. Its totient is φ = 10681856.

The previous prime is 21363703. The next prime is 21363739. The reversal of 21363728 is 82736312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18905104 + 2458624 = 4348^2 + 1568^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21363694 and 21363703.

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, 667601 + ... + 667632.

Almost surely, 2^21363728 is an apocalyptic number.

It is an amenable number.

21363728 is a deficient number, since it is larger than the sum of its proper divisors (20028526).

21363728 is a wasteful number, since it uses less digits than its factorization.

21363728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1335241 (or 1335235 counting only the distinct ones).

The product of its digits is 12096, while the sum is 32.

The square root of 21363728 is about 4622.0913015647. The cubic root of 21363728 is about 277.4761627659.

The spelling of 21363728 in words is "twenty-one million, three hundred sixty-three thousand, seven hundred twenty-eight".