646559 has 4 divisors (see below), whose sum is σ = 648720. Its totient is φ = 644400.

The previous prime is 646549. The next prime is 646571. The reversal of 646559 is 955646.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 955646 = 2 ⋅477823.

It is a cyclic number.

It is not a de Polignac number, because 646559 - 2⁴ = 646543 is a prime.

It is a Duffinian number.

Its product of digits (32400) is a multiple of the sum of its prime divisors (2160).

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 646559.

It is not an unprimeable number, because it can be changed into a prime (646519) 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, 542 + ... + 1259.

It is an arithmetic number, because the mean of its divisors is an integer number (162180).

2⁶⁴⁶⁵⁵⁹ is an apocalyptic number.

646559 is a deficient number, since it is larger than the sum of its proper divisors (2161).

646559 is a wasteful number, since it uses less digits than its factorization.

646559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2160.

The product of its digits is 32400, while the sum is 35.

The square root of 646559 is about 804.0889254305. The cubic root of 646559 is about 86.4707821174.

The spelling of 646559 in words is "six hundred forty-six thousand, five hundred fifty-nine".