688630841 has 2 divisors, whose sum is σ = 688630842. Its totient is φ = 688630840.

The previous prime is 688630763. The next prime is 688630861. The reversal of 688630841 is 148036886.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 636502441 + 52128400 = 25229^2 + 7220^2 .

It is a cyclic number.

It is not a de Polignac number, because 688630841 - 2¹⁸ = 688368697 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 688630792 and 688630801.

It is not a weakly prime, because it can be changed into another prime (688630861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344315420 + 344315421.

It is an arithmetic number, because the mean of its divisors is an integer number (344315421).

Almost surely, 2^688630841 is an apocalyptic number.

It is an amenable number.

688630841 is a deficient number, since it is larger than the sum of its proper divisors (1).

688630841 is an equidigital number, since it uses as much as digits as its factorization.

688630841 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 221184, while the sum is 44.

The square root of 688630841 is about 26241.7766357387. The cubic root of 688630841 is about 883.0707293753.

The spelling of 688630841 in words is "six hundred eighty-eight million, six hundred thirty thousand, eight hundred forty-one".