20665616 has 20 divisors (see below), whose sum is σ = 42147600. Its totient is φ = 9788832.

The previous prime is 20665577. The next prime is 20665621. The reversal of 20665616 is 61656602.

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 3 ways as a sum of consecutive naturals, for example, 33686 + ... + 34293.

It is an arithmetic number, because the mean of its divisors is an integer number (2107380).

Almost surely, 2^20665616 is an apocalyptic number.

It is an amenable number.

20665616 is an abundant number, since it is smaller than the sum of its proper divisors (21481984).

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

20665616 is a wasteful number, since it uses less digits than its factorization.

20665616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68006 (or 68000 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 20665616 is about 4545.9450062666. The cubic root of 20665616 is about 274.4202264753.

The spelling of 20665616 in words is "twenty million, six hundred sixty-five thousand, six hundred sixteen".