681388571 has 2 divisors, whose sum is σ = 681388572. Its totient is φ = 681388570.

The previous prime is 681388549. The next prime is 681388573. The reversal of 681388571 is 175883186.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681388571 - 2¹⁰ = 681387547 is a prime.

Together with 681388573, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (681388573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340694285 + 340694286.

It is an arithmetic number, because the mean of its divisors is an integer number (340694286).

Almost surely, 2^681388571 is an apocalyptic number.

681388571 is a deficient number, since it is larger than the sum of its proper divisors (1).

681388571 is an equidigital number, since it uses as much as digits as its factorization.

681388571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 322560, while the sum is 47.

The square root of 681388571 is about 26103.4206762256. The cubic root of 681388571 is about 879.9640872913.

The spelling of 681388571 in words is "six hundred eighty-one million, three hundred eighty-eight thousand, five hundred seventy-one".