681557759 has 4 divisors (see below), whose sum is σ = 717429240. Its totient is φ = 645686280.

The previous prime is 681557743. The next prime is 681557771. The reversal of 681557759 is 957755186.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 957755186 = 2 ⋅478877593.

It is a cyclic number.

It is not a de Polignac number, because 681557759 - 2⁴ = 681557743 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 681557759.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681557959) 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, 17935712 + ... + 17935749.

It is an arithmetic number, because the mean of its divisors is an integer number (179357310).

Almost surely, 2^681557759 is an apocalyptic number.

681557759 is a deficient number, since it is larger than the sum of its proper divisors (35871481).

681557759 is a wasteful number, since it uses less digits than its factorization.

681557759 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35871480.

The product of its digits is 2646000, while the sum is 53.

The square root of 681557759 is about 26106.6611997781. The cubic root of 681557759 is about 880.0369126217.

The spelling of 681557759 in words is "six hundred eighty-one million, five hundred fifty-seven thousand, seven hundred fifty-nine".