20680720 has 60 divisors (see below), whose sum is σ = 49868460. Its totient is φ = 7975680.

The previous prime is 20680711. The next prime is 20680729. The reversal of 20680720 is 2708602.

It is an interprime number because it is at equal distance from previous prime (20680711) and next prime (20680729).

It can be written as a sum of positive squares in 2 ways, for example, as 3936256 + 16744464 = 1984^2 + 4092^2 .

It is not an unprimeable number, because it can be changed into a prime (20680729) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 76746 + ... + 77014.

It is an arithmetic number, because the mean of its divisors is an integer number (831141).

Almost surely, 2^20680720 is an apocalyptic number.

20680720 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 20680720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24934230).

20680720 is an abundant number, since it is smaller than the sum of its proper divisors (29187740).

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

20680720 is a wasteful number, since it uses less digits than its factorization.

20680720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344 (or 307 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 20680720 is about 4547.6059635813. The cubic root of 20680720 is about 274.4870659011.

The spelling of 20680720 in words is "twenty million, six hundred eighty thousand, seven hundred twenty".