688686841 has 2 divisors, whose sum is σ = 688686842. Its totient is φ = 688686840.

The previous prime is 688686833. The next prime is 688686853. The reversal of 688686841 is 148686886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 651525625 + 37161216 = 25525^2 + 6096^2 .

It is a cyclic number.

It is not a de Polignac number, because 688686841 - 2³ = 688686833 is a prime.

It is not a weakly prime, because it can be changed into another prime (688686821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344343420 + 344343421.

It is an arithmetic number, because the mean of its divisors is an integer number (344343421).

Almost surely, 2^688686841 is an apocalyptic number.

It is an amenable number.

688686841 is a deficient number, since it is larger than the sum of its proper divisors (1).

688686841 is an equidigital number, since it uses as much as digits as its factorization.

688686841 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3538944, while the sum is 55.

The square root of 688686841 is about 26242.8436149743. The cubic root of 688686841 is about 883.0946660612.

The spelling of 688686841 in words is "six hundred eighty-eight million, six hundred eighty-six thousand, eight hundred forty-one".