689609921 has 64 divisors (see below), whose sum is σ = 987033600. Its totient is φ = 463968000.

The previous prime is 689609917. The next prime is 689609923. The reversal of 689609921 is 129906986.

It is a cyclic number.

It is not a de Polignac number, because 689609921 - 2² = 689609917 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 689609921.

It is not an unprimeable number, because it can be changed into a prime (689609923) 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 63 ways as a sum of consecutive naturals, for example, 1920740 + ... + 1921098.

It is an arithmetic number, because the mean of its divisors is an integer number (15422400).

Almost surely, 2^689609921 is an apocalyptic number.

It is an amenable number.

689609921 is a deficient number, since it is larger than the sum of its proper divisors (297423679).

689609921 is a wasteful number, since it uses less digits than its factorization.

689609921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510.

The product of its (nonzero) digits is 419904, while the sum is 50.

The square root of 689609921 is about 26260.4249965609. The cubic root of 689609921 is about 883.4890412906.

The spelling of 689609921 in words is "six hundred eighty-nine million, six hundred nine thousand, nine hundred twenty-one".