681594653 has 4 divisors (see below), whose sum is σ = 688621500. Its totient is φ = 674567808.

The previous prime is 681594637. The next prime is 681594659. The reversal of 681594653 is 356495186.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 356495186 = 2 ⋅178247593.

It can be written as a sum of positive squares in 2 ways, for example, as 234610489 + 446984164 = 15317^2 + 21142^2 .

It is a cyclic number.

It is not a de Polignac number, because 681594653 - 2⁴ = 681594637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 681594598 and 681594607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681594659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3513278 + ... + 3513471.

It is an arithmetic number, because the mean of its divisors is an integer number (172155375).

Almost surely, 2^681594653 is an apocalyptic number.

It is an amenable number.

681594653 is a deficient number, since it is larger than the sum of its proper divisors (7026847).

681594653 is an equidigital number, since it uses as much as digits as its factorization.

681594653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7026846.

The product of its digits is 777600, while the sum is 47.

The square root of 681594653 is about 26107.3677914875. The cubic root of 681594653 is about 880.0527916849.

The spelling of 681594653 in words is "six hundred eighty-one million, five hundred ninety-four thousand, six hundred fifty-three".