689640161 has 6 divisors (see below), whose sum is σ = 802234530. Its totient is φ = 591120096.

The previous prime is 689640143. The next prime is 689640163. The reversal of 689640161 is 161046986.

It can be written as a sum of positive squares in only one way, i.e., 504271936 + 185368225 = 22456^2 + 13615^2 .

It is a de Polignac number, because none of the positive numbers 2^k-689640161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (689640163) 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 in 5 ways as a sum of consecutive naturals, for example, 7037096 + ... + 7037193.

It is an arithmetic number, because the mean of its divisors is an integer number (133705755).

Almost surely, 2^689640161 is an apocalyptic number.

It is an amenable number.

689640161 is a deficient number, since it is larger than the sum of its proper divisors (112594369).

689640161 is a wasteful number, since it uses less digits than its factorization.

689640161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14074303 (or 14074296 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 689640161 is about 26261.0007615856. Note that the first 3 decimals coincide. The cubic root of 689640161 is about 883.5019550250.

The spelling of 689640161 in words is "six hundred eighty-nine million, six hundred forty thousand, one hundred sixty-one".