681123563 has 2 divisors, whose sum is σ = 681123564. Its totient is φ = 681123562.

The previous prime is 681123559. The next prime is 681123629. The reversal of 681123563 is 365321186.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 681123563 - 2² = 681123559 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (681123263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340561781 + 340561782.

It is an arithmetic number, because the mean of its divisors is an integer number (340561782).

Almost surely, 2^681123563 is an apocalyptic number.

681123563 is a deficient number, since it is larger than the sum of its proper divisors (1).

681123563 is an equidigital number, since it uses as much as digits as its factorization.

681123563 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25920, while the sum is 35.

The square root of 681123563 is about 26098.3440662430. The cubic root of 681123563 is about 879.8499929398.

The spelling of 681123563 in words is "six hundred eighty-one million, one hundred twenty-three thousand, five hundred sixty-three".