681139777 has 4 divisors (see below), whose sum is σ = 681480496. Its totient is φ = 680799060.

The previous prime is 681139769. The next prime is 681139793. The reversal of 681139777 is 777931186.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 681139777 - 2³ = 681139769 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 681139777.

It is not an unprimeable number, because it can be changed into a prime (681139747) 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 3 ways as a sum of consecutive naturals, for example, 167343 + ... + 171364.

It is an arithmetic number, because the mean of its divisors is an integer number (170370124).

Almost surely, 2^681139777 is an apocalyptic number.

It is an amenable number.

681139777 is a deficient number, since it is larger than the sum of its proper divisors (340719).

681139777 is a wasteful number, since it uses less digits than its factorization.

681139777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340718.

The product of its digits is 444528, while the sum is 49.

The square root of 681139777 is about 26098.6546971295. The cubic root of 681139777 is about 879.8569744311.

The spelling of 681139777 in words is "six hundred eighty-one million, one hundred thirty-nine thousand, seven hundred seventy-seven".