681305120661 has 8 divisors (see below), whose sum is σ = 990989266464. Its totient is φ = 412912194320.

The previous prime is 681305120659. The next prime is 681305120663. The reversal of 681305120661 is 166021503186.

It is an interprime number because it is at equal distance from previous prime (681305120659) and next prime (681305120663).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 681305120661 - 2¹ = 681305120659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681305120663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10322804826 + ... + 10322804891.

It is an arithmetic number, because the mean of its divisors is an integer number (123873658308).

Almost surely, 2^681305120661 is an apocalyptic number.

It is an amenable number.

681305120661 is a deficient number, since it is larger than the sum of its proper divisors (309684145803).

681305120661 is a wasteful number, since it uses less digits than its factorization.

681305120661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20645609731.

The product of its (nonzero) digits is 51840, while the sum is 39.

The spelling of 681305120661 in words is "six hundred eighty-one billion, three hundred five million, one hundred twenty thousand, six hundred sixty-one".