681247393 has 4 divisors (see below), whose sum is σ = 688270660. Its totient is φ = 674224128.

The previous prime is 681247379. The next prime is 681247417. The reversal of 681247393 is 393742186.

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 455737104 + 225510289 = 21348^2 + 15017^2 .

It is a cyclic number.

It is not a de Polignac number, because 681247393 - 2⁵ = 681247361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681247313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3511488 + ... + 3511681.

It is an arithmetic number, because the mean of its divisors is an integer number (172067665).

Almost surely, 2^681247393 is an apocalyptic number.

It is an amenable number.

681247393 is a deficient number, since it is larger than the sum of its proper divisors (7023267).

681247393 is an equidigital number, since it uses as much as digits as its factorization.

681247393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7023266.

The product of its digits is 217728, while the sum is 43.

The square root of 681247393 is about 26100.7163311661. The cubic root of 681247393 is about 879.9033093661.

The spelling of 681247393 in words is "six hundred eighty-one million, two hundred forty-seven thousand, three hundred ninety-three".