689661 has 32 divisors (see below), whose sum is σ = 1209600. Its totient is φ = 380160.

The previous prime is 689641. The next prime is 689693. The reversal of 689661 is 166986.

It is not a de Polignac number, because 689661 - 2⁵ = 689629 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 689661.

It is not an unprimeable number, because it can be changed into a prime (689621) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7705 + ... + 7793.

It is an arithmetic number, because the mean of its divisors is an integer number (37800).

2⁶⁸⁹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

689661 is a deficient number, since it is larger than the sum of its proper divisors (519939).

689661 is a wasteful number, since it uses less digits than its factorization.

689661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146 (or 140 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 689661 is about 830.4583072015. The cubic root of 689661 is about 88.3510853923.

The spelling of 689661 in words is "six hundred eighty-nine thousand, six hundred sixty-one".