681359661 has 8 divisors (see below), whose sum is σ = 1009421760. Its totient is φ = 454239756.

The previous prime is 681359647. The next prime is 681359683. The reversal of 681359661 is 166953186.

681359661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 681359661 - 2¹⁰ = 681358637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681359621) 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, 12617745 + ... + 12617798.

It is an arithmetic number, because the mean of its divisors is an integer number (126177720).

Almost surely, 2^681359661 is an apocalyptic number.

It is an amenable number.

681359661 is a deficient number, since it is larger than the sum of its proper divisors (328062099).

681359661 is a wasteful number, since it uses less digits than its factorization.

681359661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25235552 (or 25235546 counting only the distinct ones).

The product of its digits is 233280, while the sum is 45.

The square root of 681359661 is about 26102.8669115099. The cubic root of 681359661 is about 879.9516420569.

The spelling of 681359661 in words is "six hundred eighty-one million, three hundred fifty-nine thousand, six hundred sixty-one".