681379381 has 2 divisors, whose sum is σ = 681379382. Its totient is φ = 681379380.

The previous prime is 681379379. The next prime is 681379417. The reversal of 681379381 is 183973186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 662238756 + 19140625 = 25734^2 + 4375^2 .

It is a cyclic number.

It is not a de Polignac number, because 681379381 - 2¹ = 681379379 is a prime.

It is a super-2 number, since 2×681379381² = 928555721703886322, which contains 22 as substring.

Together with 681379379, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681379081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340689690 + 340689691.

It is an arithmetic number, because the mean of its divisors is an integer number (340689691).

Almost surely, 2^681379381 is an apocalyptic number.

It is an amenable number.

681379381 is a deficient number, since it is larger than the sum of its proper divisors (1).

681379381 is an equidigital number, since it uses as much as digits as its factorization.

681379381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 46.

The square root of 681379381 is about 26103.2446450628. The cubic root of 681379381 is about 879.9601312000.

The spelling of 681379381 in words is "six hundred eighty-one million, three hundred seventy-nine thousand, three hundred eighty-one".