681408875561 has 16 divisors (see below), whose sum is σ = 735159711744. Its totient is φ = 629178511104.

The previous prime is 681408875557. The next prime is 681408875621. The reversal of 681408875561 is 165578804186.

It is a cyclic number.

It is not a de Polignac number, because 681408875561 - 2² = 681408875557 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 681408875561.

It is not an unprimeable number, because it can be changed into a prime (681408875531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19627160 + ... + 19661846.

It is an arithmetic number, because the mean of its divisors is an integer number (45947481984).

Almost surely, 2^681408875561 is an apocalyptic number.

It is an amenable number.

681408875561 is a deficient number, since it is larger than the sum of its proper divisors (53750836183).

681408875561 is a wasteful number, since it uses less digits than its factorization.

681408875561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56560.

The product of its (nonzero) digits is 12902400, while the sum is 59.

The spelling of 681408875561 in words is "six hundred eighty-one billion, four hundred eight million, eight hundred seventy-five thousand, five hundred sixty-one".