778855 has 36 divisors (see below), whose sum is σ = 1259928. Its totient is φ = 456960.

The previous prime is 778847. The next prime is 778871. The reversal of 778855 is 558877.

It is not a de Polignac number, because 778855 - 2³ = 778847 is a prime.

It is a super-2 number, since 2×778855² = 1213230222050, which contains 22 as substring.

It is a Duffinian number.

Its product of digits (78400) is a multiple of the sum of its prime divisors (40).

778855 is a lucky number.

It is a zygodrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 45807 + ... + 45823.

It is an arithmetic number, because the mean of its divisors is an integer number (34998).

2⁷⁷⁸⁸⁵⁵ is an apocalyptic number.

778855 is a deficient number, since it is larger than the sum of its proper divisors (481073).

778855 is a wasteful number, since it uses less digits than its factorization.

778855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64 (or 40 counting only the distinct ones).

The product of its digits is 78400, while the sum is 40.

The square root of 778855 is about 882.5276199644. The cubic root of 778855 is about 92.0065764045.

The spelling of 778855 in words is "seven hundred seventy-eight thousand, eight hundred fifty-five".