688108621 has 2 divisors, whose sum is σ = 688108622. Its totient is φ = 688108620.

The previous prime is 688108613. The next prime is 688108627. The reversal of 688108621 is 126801886.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 686702025 + 1406596 = 26205^2 + 1186^2 .

It is a cyclic number.

It is not a de Polignac number, because 688108621 - 2³ = 688108613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688108627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344054310 + 344054311.

It is an arithmetic number, because the mean of its divisors is an integer number (344054311).

Almost surely, 2^688108621 is an apocalyptic number.

It is an amenable number.

688108621 is a deficient number, since it is larger than the sum of its proper divisors (1).

688108621 is an equidigital number, since it uses as much as digits as its factorization.

688108621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36864, while the sum is 40.

The square root of 688108621 is about 26231.8245838905. The cubic root of 688108621 is about 882.8474487291.

The spelling of 688108621 in words is "six hundred eighty-eight million, one hundred eight thousand, six hundred twenty-one".