681872779 has 48 divisors (see below), whose sum is σ = 863846400. Its totient is φ = 534957696.

The previous prime is 681872777. The next prime is 681872797. The reversal of 681872779 is 977278186.

It is a happy number.

It is not a de Polignac number, because 681872779 - 2¹ = 681872777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (681872773) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 5369014 + ... + 5369140.

It is an arithmetic number, because the mean of its divisors is an integer number (17996800).

Almost surely, 2^681872779 is an apocalyptic number.

681872779 is a deficient number, since it is larger than the sum of its proper divisors (181973621).

681872779 is a wasteful number, since it uses less digits than its factorization.

681872779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312 (or 305 counting only the distinct ones).

The product of its digits is 2370816, while the sum is 55.

The square root of 681872779 is about 26112.6938288642. The cubic root of 681872779 is about 880.1724778145.

It can be divided in two parts, 6818 and 72779, that added together give a palindrome (79597).

The spelling of 681872779 in words is "six hundred eighty-one million, eight hundred seventy-two thousand, seven hundred seventy-nine".