686412778 has 8 divisors (see below), whose sum is σ = 1030981572. Its totient is φ = 342752256.

The previous prime is 686412733. The next prime is 686412787. The reversal of 686412778 is 877214686.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 597166969 + 89245809 = 24437^2 + 9447^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225175 + ... + 228202.

Almost surely, 2^686412778 is an apocalyptic number.

686412778 is a deficient number, since it is larger than the sum of its proper divisors (344568794).

686412778 is a wasteful number, since it uses less digits than its factorization.

686412778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454136.

The product of its digits is 903168, while the sum is 49.

The square root of 686412778 is about 26199.4804910326. The cubic root of 686412778 is about 882.1215932308.

The spelling of 686412778 in words is "six hundred eighty-six million, four hundred twelve thousand, seven hundred seventy-eight".