646489 has 4 divisors (see below), whose sum is σ = 651280. Its totient is φ = 641700.

The previous prime is 646453. The next prime is 646519. The reversal of 646489 is 984646.

646489 = T₆₅₅ + T₆₅₆ + T₆₅₇.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 646489 - 2¹⁹ = 122201 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (646189) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2187 + ... + 2464.

It is an arithmetic number, because the mean of its divisors is an integer number (162820).

2⁶⁴⁶⁴⁸⁹ is an apocalyptic number.

646489 is the 657-th centered triangular number.

It is an amenable number.

646489 is a deficient number, since it is larger than the sum of its proper divisors (4791).

646489 is a wasteful number, since it uses less digits than its factorization.

646489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4790.

The product of its digits is 41472, while the sum is 37.

The square root of 646489 is about 804.0453967283. The cubic root of 646489 is about 86.4676614054.

The spelling of 646489 in words is "six hundred forty-six thousand, four hundred eighty-nine".