20807680 has 64 divisors (see below), whose sum is σ = 50330880. Its totient is φ = 8257536.

The previous prime is 20807629. The next prime is 20807687. The reversal of 20807680 is 8670802.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20807687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163777 + ... + 163903.

It is an arithmetic number, because the mean of its divisors is an integer number (786420).

Almost surely, 2^20807680 is an apocalyptic number.

20807680 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 20807680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25165440).

20807680 is an abundant number, since it is smaller than the sum of its proper divisors (29523200).

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

20807680 is an frugal number, since it uses more digits than its factorization.

20807680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 20807680 is about 4561.5435983886. The cubic root of 20807680 is about 275.0476170988.

The spelling of 20807680 in words is "twenty million, eight hundred seven thousand, six hundred eighty".