689609689 has 2 divisors, whose sum is σ = 689609690. Its totient is φ = 689609688.

The previous prime is 689609603. The next prime is 689609707. The reversal of 689609689 is 986906986.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 517790025 + 171819664 = 22755^2 + 13108^2 .

It is a cyclic number.

It is not a de Polignac number, because 689609689 - 2¹⁷ = 689478617 is a prime.

689609689 is a strobogrammatic number because it is the same when read upside-down.

It is not a weakly prime, because it can be changed into another prime (689609489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344804844 + 344804845.

It is an arithmetic number, because the mean of its divisors is an integer number (344804845).

Almost surely, 2^689609689 is an apocalyptic number.

It is an amenable number.

689609689 is a deficient number, since it is larger than the sum of its proper divisors (1).

689609689 is an equidigital number, since it uses as much as digits as its factorization.

689609689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10077696, while the sum is 61.

The square root of 689609689 is about 26260.4205792672. The cubic root of 689609689 is about 883.4889422155.

The spelling of 689609689 in words is "six hundred eighty-nine million, six hundred nine thousand, six hundred eighty-nine".