20665601 has 8 divisors (see below), whose sum is σ = 22970304. Its totient is φ = 18431920.

The previous prime is 20665577. The next prime is 20665621. The reversal of 20665601 is 10656602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20665601 - 2⁶ = 20665537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20665621) by changing a digit.

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, 17141 + ... + 18306.

It is an arithmetic number, because the mean of its divisors is an integer number (2871288).

Almost surely, 2^20665601 is an apocalyptic number.

It is an amenable number.

20665601 is a deficient number, since it is larger than the sum of its proper divisors (2304703).

20665601 is a wasteful number, since it uses less digits than its factorization.

20665601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35511.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20665601 is about 4545.9433564443. The cubic root of 20665601 is about 274.4201600799.

It can be divided in two parts, 2066 and 5601, that added together give a palindrome (7667).

The spelling of 20665601 in words is "twenty million, six hundred sixty-five thousand, six hundred one".