778641 has 4 divisors (see below), whose sum is σ = 1038192. Its totient is φ = 519092.

The previous prime is 778633. The next prime is 778643. The reversal of 778641 is 146877.

778641 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 778641 - 2³ = 778633 is a prime.

It is a D-number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 778641.

It is not an unprimeable number, because it can be changed into a prime (778643) 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, 129771 + ... + 129776.

It is an arithmetic number, because the mean of its divisors is an integer number (259548).

2⁷⁷⁸⁶⁴¹ is an apocalyptic number.

It is an amenable number.

778641 is a deficient number, since it is larger than the sum of its proper divisors (259551).

778641 is a wasteful number, since it uses less digits than its factorization.

778641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259550.

The product of its digits is 9408, while the sum is 33.

The square root of 778641 is about 882.4063689707. The cubic root of 778641 is about 91.9981489861.

The spelling of 778641 in words is "seven hundred seventy-eight thousand, six hundred forty-one".