681139778 has 64 divisors (see below), whose sum is σ = 1213056000. Its totient is φ = 283550400.

The previous prime is 681139769. The next prime is 681139793. The reversal of 681139778 is 877931186.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1750808 + ... + 1751196.

It is an arithmetic number, because the mean of its divisors is an integer number (18954000).

Almost surely, 2^681139778 is an apocalyptic number.

681139778 is a deficient number, since it is larger than the sum of its proper divisors (531916222).

681139778 is a wasteful number, since it uses less digits than its factorization.

681139778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551.

The product of its digits is 508032, while the sum is 50.

The square root of 681139778 is about 26098.6547162876. The cubic root of 681139778 is about 879.8569748616.

The spelling of 681139778 in words is "six hundred eighty-one million, one hundred thirty-nine thousand, seven hundred seventy-eight".