780645 has 16 divisors (see below), whose sum is σ = 1268352. Its totient is φ = 409920.

The previous prime is 780631. The next prime is 780649. The reversal of 780645 is 546087.

It is a happy number.

It is not a de Polignac number, because 780645 - 2⁵ = 780613 is a prime.

780645 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (780649) 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, 699 + ... + 1431.

It is an arithmetic number, because the mean of its divisors is an integer number (79272).

2⁷⁸⁰⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

780645 is a deficient number, since it is larger than the sum of its proper divisors (487707).

780645 is a wasteful number, since it uses less digits than its factorization.

780645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 812.

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 780645 is about 883.5411705178. The cubic root of 780645 is about 92.0770070432.

The spelling of 780645 in words is "seven hundred eighty thousand, six hundred forty-five".