21665336 has 32 divisors (see below), whose sum is σ = 50647680. Its totient is φ = 8440800.

The previous prime is 21665279. The next prime is 21665341. The reversal of 21665336 is 63356612.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a congruent number.

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 in 7 ways as a sum of consecutive naturals, for example, 16970 + ... + 18201.

It is an arithmetic number, because the mean of its divisors is an integer number (1582740).

Almost surely, 2^21665336 is an apocalyptic number.

It is an amenable number.

21665336 is an abundant number, since it is smaller than the sum of its proper divisors (28982344).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21665336 is a wasteful number, since it uses less digits than its factorization.

21665336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35195 (or 35191 counting only the distinct ones).

The product of its digits is 19440, while the sum is 32.

The square root of 21665336 is about 4654.6037425328. The cubic root of 21665336 is about 278.7758463034.

The spelling of 21665336 in words is "twenty-one million, six hundred sixty-five thousand, three hundred thirty-six".