698638609 has 2 divisors, whose sum is σ = 698638610. Its totient is φ = 698638608.

The previous prime is 698638601. The next prime is 698638627. The reversal of 698638609 is 906836896.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 484660225 + 213978384 = 22015^2 + 14628^2 .

It is a cyclic number.

It is not a de Polignac number, because 698638609 - 2³ = 698638601 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 698638609.

It is not a weakly prime, because it can be changed into another prime (698638601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 349319304 + 349319305.

It is an arithmetic number, because the mean of its divisors is an integer number (349319305).

Almost surely, 2^698638609 is an apocalyptic number.

It is an amenable number.

698638609 is a deficient number, since it is larger than the sum of its proper divisors (1).

698638609 is an equidigital number, since it uses as much as digits as its factorization.

698638609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3359232, while the sum is 55.

The square root of 698638609 is about 26431.7727176972. The cubic root of 698638609 is about 887.3280165058.

The spelling of 698638609 in words is "six hundred ninety-eight million, six hundred thirty-eight thousand, six hundred nine".