779978 has 4 divisors (see below), whose sum is σ = 1169970. Its totient is φ = 389988.

The previous prime is 779971. The next prime is 779981. The reversal of 779978 is 879977.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 879977 = 7 ⋅125711.

It can be written as a sum of positive squares in only one way, i.e., 779689 + 289 = 883^2 + 17^2 .

It is not an unprimeable number, because it can be changed into a prime (779971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 194993 + ... + 194996.

2⁷⁷⁹⁹⁷⁸ is an apocalyptic number.

779978 is a deficient number, since it is larger than the sum of its proper divisors (389992).

779978 is a wasteful number, since it uses less digits than its factorization.

779978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389991.

The product of its digits is 222264, while the sum is 47.

The square root of 779978 is about 883.1636314976. The cubic root of 779978 is about 92.0507753742.

Subtracting 779978 from its reverse (879977), we obtain a palindrome (99999).

The spelling of 779978 in words is "seven hundred seventy-nine thousand, nine hundred seventy-eight".