780345 has 12 divisors (see below), whose sum is σ = 1352676. Its totient is φ = 416160.

The previous prime is 780343. The next prime is 780347. The reversal of 780345 is 543087.

It is an interprime number because it is at equal distance from previous prime (780343) and next prime (780347).

It can be written as a sum of positive squares in 2 ways, for example, as 514089 + 266256 = 717^2 + 516^2 .

It is not a de Polignac number, because 780345 - 2¹ = 780343 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (780343) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 8626 + ... + 8715.

It is an arithmetic number, because the mean of its divisors is an integer number (112723).

2⁷⁸⁰³⁴⁵ is an apocalyptic number.

It is an amenable number.

780345 is a deficient number, since it is larger than the sum of its proper divisors (572331).

780345 is a wasteful number, since it uses less digits than its factorization.

780345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17352 (or 17349 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 780345 is about 883.3713828283. The cubic root of 780345 is about 92.0652105410.

The spelling of 780345 in words is "seven hundred eighty thousand, three hundred forty-five".