681725257 has 2 divisors, whose sum is σ = 681725258. Its totient is φ = 681725256.

The previous prime is 681725237. The next prime is 681725293. The reversal of 681725257 is 752527186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 531809721 + 149915536 = 23061^2 + 12244^2 .

It is a cyclic number.

It is not a de Polignac number, because 681725257 - 2¹⁵ = 681692489 is a prime.

It is not a weakly prime, because it can be changed into another prime (681725237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340862628 + 340862629.

It is an arithmetic number, because the mean of its divisors is an integer number (340862629).

Almost surely, 2^681725257 is an apocalyptic number.

It is an amenable number.

681725257 is a deficient number, since it is larger than the sum of its proper divisors (1).

681725257 is an equidigital number, since it uses as much as digits as its factorization.

681725257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 235200, while the sum is 43.

The square root of 681725257 is about 26109.8689579247. The cubic root of 681725257 is about 880.1089986371.

The spelling of 681725257 in words is "six hundred eighty-one million, seven hundred twenty-five thousand, two hundred fifty-seven".