20306664 has 96 divisors (see below), whose sum is σ = 64384320. Its totient is φ = 5660928.

The previous prime is 20306651. The next prime is 20306681. The reversal of 20306664 is 46660302.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21204 + ... + 22140.

It is an arithmetic number, because the mean of its divisors is an integer number (670670).

Almost surely, 2^20306664 is an apocalyptic number.

20306664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20306664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32192160).

20306664 is an abundant number, since it is smaller than the sum of its proper divisors (44077656).

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

20306664 is a wasteful number, since it uses less digits than its factorization.

20306664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999 (or 992 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 20306664 is about 4506.2916017497. The cubic root of 20306664 is about 272.8220875183.

Adding to 20306664 its reverse (46660302), we get a palindrome (66966966).

The spelling of 20306664 in words is "twenty million, three hundred six thousand, six hundred sixty-four".