646546 has 4 divisors (see below), whose sum is σ = 969822. Its totient is φ = 323272.

The previous prime is 646543. The next prime is 646549. The reversal of 646546 is 645646.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (646543) and next prime (646549).

It can be written as a sum of positive squares in only one way, i.e., 622521 + 24025 = 789^2 + 155^2 .

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (646543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161635 + ... + 161638.

2⁶⁴⁶⁵⁴⁶ is an apocalyptic number.

646546 is a deficient number, since it is larger than the sum of its proper divisors (323276).

646546 is a wasteful number, since it uses less digits than its factorization.

646546 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323275.

The product of its digits is 17280, while the sum is 31.

The square root of 646546 is about 804.0808417069. The cubic root of 646546 is about 86.4702025736.

Subtracting from 646546 its reverse (645646), we obtain a square (900 = 30²).

The spelling of 646546 in words is "six hundred forty-six thousand, five hundred forty-six".