671256778 has 4 divisors (see below), whose sum is σ = 1006885170. Its totient is φ = 335628388.

The previous prime is 671256767. The next prime is 671256787. The reversal of 671256778 is 877652176.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 435849129 + 235407649 = 20877^2 + 15343^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 167814193 + ... + 167814196.

Almost surely, 2^671256778 is an apocalyptic number.

671256778 is a deficient number, since it is larger than the sum of its proper divisors (335628392).

671256778 is a wasteful number, since it uses less digits than its factorization.

671256778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335628391.

The product of its digits is 987840, while the sum is 49.

The square root of 671256778 is about 25908.6236222614. The cubic root of 671256778 is about 875.5807966592.

The spelling of 671256778 in words is "six hundred seventy-one million, two hundred fifty-six thousand, seven hundred seventy-eight".