681385937 has 2 divisors, whose sum is σ = 681385938. Its totient is φ = 681385936.

The previous prime is 681385933. The next prime is 681385987. The reversal of 681385937 is 739583186.

It is a happy number.

It is an a-pointer prime, because the next prime (681385987) can be obtained adding 681385937 to its sum of digits (50).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 653518096 + 27867841 = 25564^2 + 5279^2 .

It is a cyclic number.

It is not a de Polignac number, because 681385937 - 2² = 681385933 is a prime.

It is not a weakly prime, because it can be changed into another prime (681385933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340692968 + 340692969.

It is an arithmetic number, because the mean of its divisors is an integer number (340692969).

Almost surely, 2^681385937 is an apocalyptic number.

It is an amenable number.

681385937 is a deficient number, since it is larger than the sum of its proper divisors (1).

681385937 is an equidigital number, since it uses as much as digits as its factorization.

681385937 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 50.

The square root of 681385937 is about 26103.3702230191. The cubic root of 681385937 is about 879.9629534163.

The spelling of 681385937 in words is "six hundred eighty-one million, three hundred eighty-five thousand, nine hundred thirty-seven".