778161 has 4 divisors (see below), whose sum is σ = 1037552. Its totient is φ = 518772.

The previous prime is 778153. The next prime is 778163. The reversal of 778161 is 161877.

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, and also an emirpimes, since its reverse is a distinct semiprime: 161877 = 3 ⋅53959.

It is not a de Polignac number, because 778161 - 2³ = 778153 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (778163) 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, 129691 + ... + 129696.

It is an arithmetic number, because the mean of its divisors is an integer number (259388).

2⁷⁷⁸¹⁶¹ is an apocalyptic number.

It is an amenable number.

778161 is a deficient number, since it is larger than the sum of its proper divisors (259391).

778161 is a wasteful number, since it uses less digits than its factorization.

778161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259390.

The product of its digits is 2352, while the sum is 30.

The square root of 778161 is about 882.1343435101. The cubic root of 778161 is about 91.9792407478.

It can be divided in two parts, 778 and 161, that added together give a palindrome (939).

The spelling of 778161 in words is "seven hundred seventy-eight thousand, one hundred sixty-one".