681097679 has 4 divisors (see below), whose sum is σ = 691263384. Its totient is φ = 670931976.

The previous prime is 681097667. The next prime is 681097717. The reversal of 681097679 is 976790186.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681097679 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 681097679.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681097609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5082752 + ... + 5082885.

It is an arithmetic number, because the mean of its divisors is an integer number (172815846).

Almost surely, 2^681097679 is an apocalyptic number.

681097679 is a deficient number, since it is larger than the sum of its proper divisors (10165705).

681097679 is a wasteful number, since it uses less digits than its factorization.

681097679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10165704.

The product of its (nonzero) digits is 1143072, while the sum is 53.

The square root of 681097679 is about 26097.8481680004. The cubic root of 681097679 is about 879.8388474703.

The spelling of 681097679 in words is "six hundred eighty-one million, ninety-seven thousand, six hundred seventy-nine".