16720385 has 24 divisors (see below), whose sum is σ = 22838760. Its totient is φ = 11728640.

The previous prime is 16720369. The next prime is 16720409. The reversal of 16720385 is 58302761.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1385329 + 15335056 = 1177^2 + 3916^2 .

It is not a de Polignac number, because 16720385 - 2⁴ = 16720369 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17069 + ... + 18021.

It is an arithmetic number, because the mean of its divisors is an integer number (951615).

Almost surely, 2^16720385 is an apocalyptic number.

It is an amenable number.

16720385 is a deficient number, since it is larger than the sum of its proper divisors (6118375).

16720385 is a wasteful number, since it uses less digits than its factorization.

16720385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1009 (or 998 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 16720385 is about 4089.0567371950. The cubic root of 16720385 is about 255.7106155871.

The spelling of 16720385 in words is "sixteen million, seven hundred twenty thousand, three hundred eighty-five".