20131665 has 8 divisors (see below), whose sum is σ = 32210688. Its totient is φ = 10736880.

The previous prime is 20131609. The next prime is 20131667. The reversal of 20131665 is 56613102.

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

It is not a de Polignac number, because 20131665 - 2¹⁶ = 20066129 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20131667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 671041 + ... + 671070.

It is an arithmetic number, because the mean of its divisors is an integer number (4026336).

Almost surely, 2^20131665 is an apocalyptic number.

It is an amenable number.

20131665 is a deficient number, since it is larger than the sum of its proper divisors (12079023).

20131665 is a wasteful number, since it uses less digits than its factorization.

20131665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1342119.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 20131665 is about 4486.8324015947. The cubic root of 20131665 is about 272.0361156269.

Adding to 20131665 its reverse (56613102), we get a palindrome (76744767).

The spelling of 20131665 in words is "twenty million, one hundred thirty-one thousand, six hundred sixty-five".