681221650857 has 12 divisors (see below), whose sum is σ = 990874752336. Its totient is φ = 412858733040.

The previous prime is 681221650829. The next prime is 681221650861. The reversal of 681221650857 is 758056122186.

It is not a de Polignac number, because 681221650857 - 2¹⁵ = 681221618089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (681221650657) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4669503 + ... + 4813179.

It is an arithmetic number, because the mean of its divisors is an integer number (82572896028).

Almost surely, 2^681221650857 is an apocalyptic number.

It is an amenable number.

681221650857 is a deficient number, since it is larger than the sum of its proper divisors (309653101479).

681221650857 is an frugal number, since it uses more digits than its factorization.

681221650857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287368 (or 143691 counting only the distinct ones).

The product of its (nonzero) digits is 1612800, while the sum is 51.

The spelling of 681221650857 in words is "six hundred eighty-one billion, two hundred twenty-one million, six hundred fifty thousand, eight hundred fifty-seven".