681563479 has 2 divisors, whose sum is σ = 681563480. Its totient is φ = 681563478.

The previous prime is 681563413. The next prime is 681563527. The reversal of 681563479 is 974365186.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681563479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681563579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340781739 + 340781740.

It is an arithmetic number, because the mean of its divisors is an integer number (340781740).

Almost surely, 2^681563479 is an apocalyptic number.

681563479 is a deficient number, since it is larger than the sum of its proper divisors (1).

681563479 is an equidigital number, since it uses as much as digits as its factorization.

681563479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 49.

The square root of 681563479 is about 26106.7707501330. The cubic root of 681563479 is about 880.0393745295.

The spelling of 681563479 in words is "six hundred eighty-one million, five hundred sixty-three thousand, four hundred seventy-nine".