681856845 has 16 divisors (see below), whose sum is σ = 1128591360. Its totient is φ = 351116864.

The previous prime is 681856801. The next prime is 681856853. The reversal of 681856845 is 548658186.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 681856845 - 2¹⁰ = 681855821 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 783309 + ... + 784178.

It is an arithmetic number, because the mean of its divisors is an integer number (70536960).

Almost surely, 2^681856845 is an apocalyptic number.

It is an amenable number.

681856845 is a deficient number, since it is larger than the sum of its proper divisors (446734515).

681856845 is a wasteful number, since it uses less digits than its factorization.

681856845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1567524.

The product of its digits is 1843200, while the sum is 51.

The square root of 681856845 is about 26112.3887264264. The cubic root of 681856845 is about 880.1656218056.

The spelling of 681856845 in words is "six hundred eighty-one million, eight hundred fifty-six thousand, eight hundred forty-five".