681326593 has 4 divisors (see below), whose sum is σ = 690659908. Its totient is φ = 671993280.

The previous prime is 681326509. The next prime is 681326603. The reversal of 681326593 is 395623186.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 257666704 + 423659889 = 16052^2 + 20583^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681326593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681326293) 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, 4666548 + ... + 4666693.

It is an arithmetic number, because the mean of its divisors is an integer number (172664977).

Almost surely, 2^681326593 is an apocalyptic number.

It is an amenable number.

681326593 is a deficient number, since it is larger than the sum of its proper divisors (9333315).

681326593 is an equidigital number, since it uses as much as digits as its factorization.

681326593 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9333314.

The product of its digits is 233280, while the sum is 43.

The square root of 681326593 is about 26102.2334868110. The cubic root of 681326593 is about 879.9374064466.

The spelling of 681326593 in words is "six hundred eighty-one million, three hundred twenty-six thousand, five hundred ninety-three".