20131664 has 40 divisors (see below), whose sum is σ = 44878080. Its totient is φ = 8569728.

The previous prime is 20131609. The next prime is 20131667. The reversal of 20131664 is 46613102.

It is a happy number.

It is a congruent number.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18857 + ... + 19895.

It is an arithmetic number, because the mean of its divisors is an integer number (1121952).

Almost surely, 2^20131664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20131664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22439040).

20131664 is an abundant number, since it is smaller than the sum of its proper divisors (24746416).

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

20131664 is a wasteful number, since it uses less digits than its factorization.

20131664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1227 (or 1221 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 20131664 is about 4486.8322901575. The cubic root of 20131664 is about 272.0361111226.

Adding to 20131664 its reverse (46613102), we get a palindrome (66744766).

The spelling of 20131664 in words is "twenty million, one hundred thirty-one thousand, six hundred sixty-four".