20311680 has 128 divisors (see below), whose sum is σ = 66096000. Its totient is φ = 5304320.

The previous prime is 20311679. The next prime is 20311693. The reversal of 20311680 is 8611302.

It is a tau number, because it is divible by the number of its divisors (128).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 136246 + ... + 136394.

It is an arithmetic number, because the mean of its divisors is an integer number (516375).

Almost surely, 2^20311680 is an apocalyptic number.

20311680 is a gapful number since it is divisible by the number (20) 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 20311680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33048000).

20311680 is an abundant number, since it is smaller than the sum of its proper divisors (45784320).

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

20311680 is a wasteful number, since it uses less digits than its factorization.

20311680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242 (or 230 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 20311680 is about 4506.8481225797. The cubic root of 20311680 is about 272.8445491583.

Adding to 20311680 its reverse (8611302), we get a palindrome (28922982).

The spelling of 20311680 in words is "twenty million, three hundred eleven thousand, six hundred eighty".