778663994 has 8 divisors (see below), whose sum is σ = 1168268340. Its totient is φ = 389241216.

The previous prime is 778663987. The next prime is 778663999. The reversal of 778663994 is 499366877.

It can be written as a sum of positive squares in 2 ways, for example, as 549292969 + 229371025 = 23437^2 + 15145^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (778663999) 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, 34109 + ... + 52160.

Almost surely, 2^778663994 is an apocalyptic number.

778663994 is a deficient number, since it is larger than the sum of its proper divisors (389604346).

778663994 is a wasteful number, since it uses less digits than its factorization.

778663994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90784.

The product of its digits is 13716864, while the sum is 59.

The square root of 778663994 is about 27904.5514925433. The cubic root of 778663994 is about 919.9905457441.

The spelling of 778663994 in words is "seven hundred seventy-eight million, six hundred sixty-three thousand, nine hundred ninety-four".