681816407 has 2 divisors, whose sum is σ = 681816408. Its totient is φ = 681816406.

The previous prime is 681816403. The next prime is 681816413. The reversal of 681816407 is 704618186.

681816407 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 681816407 - 2² = 681816403 is a prime.

It is a super-2 number, since 2×681816407² = 929747225708779298, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681816403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340908203 + 340908204.

It is an arithmetic number, because the mean of its divisors is an integer number (340908204).

Almost surely, 2^681816407 is an apocalyptic number.

681816407 is a deficient number, since it is larger than the sum of its proper divisors (1).

681816407 is an equidigital number, since it uses as much as digits as its factorization.

681816407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64512, while the sum is 41.

The square root of 681816407 is about 26111.6144081518. The cubic root of 681816407 is about 880.1482218478.

The spelling of 681816407 in words is "six hundred eighty-one million, eight hundred sixteen thousand, four hundred seven".