21283664 has 10 divisors (see below), whose sum is σ = 41237130. Its totient is φ = 10641824.

The previous prime is 21283657. The next prime is 21283673. The reversal of 21283664 is 46638212.

It can be written as a sum of positive squares in only one way, i.e., 19009600 + 2274064 = 4360^2 + 1508^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21283664.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665099 + ... + 665130.

It is an arithmetic number, because the mean of its divisors is an integer number (4123713).

Almost surely, 2^21283664 is an apocalyptic number.

It is an amenable number.

21283664 is a deficient number, since it is larger than the sum of its proper divisors (19953466).

21283664 is a wasteful number, since it uses less digits than its factorization.

21283664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1330237 (or 1330231 counting only the distinct ones).

The product of its digits is 13824, while the sum is 32.

The square root of 21283664 is about 4613.4221571411. The cubic root of 21283664 is about 277.1291000262.

The spelling of 21283664 in words is "twenty-one million, two hundred eighty-three thousand, six hundred sixty-four".