681663379 has 2 divisors, whose sum is σ = 681663380. Its totient is φ = 681663378.

The previous prime is 681663343. The next prime is 681663383. The reversal of 681663379 is 973366186.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681663379 - 2⁷ = 681663251 is a prime.

It is not a weakly prime, because it can be changed into another prime (681663179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340831689 + 340831690.

It is an arithmetic number, because the mean of its divisors is an integer number (340831690).

Almost surely, 2^681663379 is an apocalyptic number.

681663379 is a deficient number, since it is larger than the sum of its proper divisors (1).

681663379 is an equidigital number, since it uses as much as digits as its factorization.

681663379 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 49.

The square root of 681663379 is about 26108.6839767921. The cubic root of 681663379 is about 880.0823696142.

The spelling of 681663379 in words is "six hundred eighty-one million, six hundred sixty-three thousand, three hundred seventy-nine".