681455778 has 16 divisors (see below), whose sum is σ = 1443083040. Its totient is φ = 213790016.

The previous prime is 681455777. The next prime is 681455809. The reversal of 681455778 is 877554186.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 681455778.

It is not an unprimeable number, because it can be changed into a prime (681455777) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3340368 + ... + 3340571.

It is an arithmetic number, because the mean of its divisors is an integer number (90192690).

Almost surely, 2^681455778 is an apocalyptic number.

681455778 is an abundant number, since it is smaller than the sum of its proper divisors (761627262).

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

681455778 is a wasteful number, since it uses less digits than its factorization.

681455778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6680961.

The product of its digits is 1881600, while the sum is 51.

The square root of 681455778 is about 26104.7079661888. The cubic root of 681455778 is about 879.9930173344.

The spelling of 681455778 in words is "six hundred eighty-one million, four hundred fifty-five thousand, seven hundred seventy-eight".