16780865 has 4 divisors (see below), whose sum is σ = 20137044. Its totient is φ = 13424688.

The previous prime is 16780843. The next prime is 16780867. The reversal of 16780865 is 56808761.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9168784 + 7612081 = 3028^2 + 2759^2 .

It is a cyclic number.

It is not a de Polignac number, because 16780865 - 2⁶ = 16780801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16780867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1678082 + ... + 1678091.

It is an arithmetic number, because the mean of its divisors is an integer number (5034261).

Almost surely, 2^16780865 is an apocalyptic number.

It is an amenable number.

16780865 is a deficient number, since it is larger than the sum of its proper divisors (3356179).

16780865 is an equidigital number, since it uses as much as digits as its factorization.

16780865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3356178.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 16780865 is about 4096.4454103527. The cubic root of 16780865 is about 256.0185584284.

The spelling of 16780865 in words is "sixteen million, seven hundred eighty thousand, eight hundred sixty-five".