681674778 has 36 divisors (see below), whose sum is σ = 1533719850. Its totient is φ = 227220552.

The previous prime is 681674753. The next prime is 681674813. The reversal of 681674778 is 877476186.

681674778 is a `hidden beast` number, since 6 + 8 + 167 + 477 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 642774609 + 38900169 = 25353^2 + 6237^2 .

It is a super-2 number, since 2×681674778² = 929361005922698568, which contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 12853 + ... + 39096.

Almost surely, 2^681674778 is an apocalyptic number.

681674778 is an abundant number, since it is smaller than the sum of its proper divisors (852045072).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

681674778 is an frugal number, since it uses more digits than its factorization.

681674778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51975 (or 51954 counting only the distinct ones).

The product of its digits is 3161088, while the sum is 54.

The square root of 681674778 is about 26108.9022748947. The cubic root of 681674778 is about 880.0872752628.

The spelling of 681674778 in words is "six hundred eighty-one million, six hundred seventy-four thousand, seven hundred seventy-eight".