689438081 has 2 divisors, whose sum is σ = 689438082. Its totient is φ = 689438080.

The previous prime is 689438051. The next prime is 689438117. The reversal of 689438081 is 180834986.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 369600625 + 319837456 = 19225^2 + 17884^2 .

It is a cyclic number.

It is not a de Polignac number, because 689438081 - 2⁶ = 689438017 is a prime.

It is a super-2 number, since 2×689438081² = 950649735065925122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (689438051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344719040 + 344719041.

It is an arithmetic number, because the mean of its divisors is an integer number (344719041).

Almost surely, 2^689438081 is an apocalyptic number.

It is an amenable number.

689438081 is a deficient number, since it is larger than the sum of its proper divisors (1).

689438081 is an equidigital number, since it uses as much as digits as its factorization.

689438081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 331776, while the sum is 47.

The square root of 689438081 is about 26257.1529492441. The cubic root of 689438081 is about 883.4156513135.

The spelling of 689438081 in words is "six hundred eighty-nine million, four hundred thirty-eight thousand, eighty-one".