681546655 has 4 divisors (see below), whose sum is σ = 817855992. Its totient is φ = 545237320.

The previous prime is 681546653. The next prime is 681546659. The reversal of 681546655 is 556645186.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 556645186 = 2 ⋅278322593.

It is not a de Polignac number, because 681546655 - 2¹ = 681546653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681546653) 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, 68154661 + ... + 68154670.

It is an arithmetic number, because the mean of its divisors is an integer number (204463998).

Almost surely, 2^681546655 is an apocalyptic number.

681546655 is a deficient number, since it is larger than the sum of its proper divisors (136309337).

681546655 is a wasteful number, since it uses less digits than its factorization.

681546655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136309336.

The product of its digits is 864000, while the sum is 46.

The square root of 681546655 is about 26106.4485328817. The cubic root of 681546655 is about 880.0321333824.

The spelling of 681546655 in words is "six hundred eighty-one million, five hundred forty-six thousand, six hundred fifty-five".