681422857 has 2 divisors, whose sum is σ = 681422858. Its totient is φ = 681422856.

The previous prime is 681422851. The next prime is 681422867. The reversal of 681422857 is 758224186.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 608559561 + 72863296 = 24669^2 + 8536^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681422857 is a prime.

It is a super-2 number, since 2×681422857² = 928674220084084898, which contains 22 as substring.

It is a zygodrome in base 14.

It is not a weakly prime, because it can be changed into another prime (681422851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340711428 + 340711429.

It is an arithmetic number, because the mean of its divisors is an integer number (340711429).

Almost surely, 2^681422857 is an apocalyptic number.

It is an amenable number.

681422857 is a deficient number, since it is larger than the sum of its proper divisors (1).

681422857 is an equidigital number, since it uses as much as digits as its factorization.

681422857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 215040, while the sum is 43.

The square root of 681422857 is about 26104.0774018160. The cubic root of 681422857 is about 879.9788463407.

The spelling of 681422857 in words is "six hundred eighty-one million, four hundred twenty-two thousand, eight hundred fifty-seven".