16820720 has 80 divisors (see below), whose sum is σ = 45681600. Its totient is φ = 5757696.

The previous prime is 16820717. The next prime is 16820729. The reversal of 16820720 is 2702861.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 16820720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16820729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27134 + ... + 27746.

It is an arithmetic number, because the mean of its divisors is an integer number (571020).

Almost surely, 2^16820720 is an apocalyptic number.

16820720 is a gapful number since it is divisible by the number (10) 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 16820720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22840800).

16820720 is an abundant number, since it is smaller than the sum of its proper divisors (28860880).

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

16820720 is an equidigital number, since it uses as much as digits as its factorization.

16820720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 647 (or 627 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 16820720 is about 4101.3071087155. The cubic root of 16820720 is about 256.2210818051.

It can be divided in two parts, 16820 and 720, that multiplied together give a square (12110400 = 3480²).

The spelling of 16820720 in words is "sixteen million, eight hundred twenty thousand, seven hundred twenty".