21283904 has 14 divisors (see below), whose sum is σ = 42235374. Its totient is φ = 10641920.

The previous prime is 21283897. The next prime is 21283919. The reversal of 21283904 is 40938212.

It can be written as a sum of positive squares in only one way, i.e., 21160000 + 123904 = 4600^2 + 352^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166217 + ... + 166344.

Almost surely, 2^21283904 is an apocalyptic number.

It is an amenable number.

21283904 is a deficient number, since it is larger than the sum of its proper divisors (20951470).

21283904 is an equidigital number, since it uses as much as digits as its factorization.

21283904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332573 (or 332563 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 21283904 is about 4613.4481681276. The cubic root of 21283904 is about 277.1301416816.

The spelling of 21283904 in words is "twenty-one million, two hundred eighty-three thousand, nine hundred four".