646511 has 4 divisors (see below), whose sum is σ = 651000. Its totient is φ = 642024.

The previous prime is 646453. The next prime is 646519. The reversal of 646511 is 115646.

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

It is a cyclic number.

It is not a de Polignac number, because 646511 - 2¹⁴ = 630127 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 2021 + ... + 2318.

It is an arithmetic number, because the mean of its divisors is an integer number (162750).

2⁶⁴⁶⁵¹¹ is an apocalyptic number.

646511 is a deficient number, since it is larger than the sum of its proper divisors (4489).

646511 is a wasteful number, since it uses less digits than its factorization.

646511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4488.

The product of its digits is 720, while the sum is 23.

The square root of 646511 is about 804.0590774315. The cubic root of 646511 is about 86.4686422249.

The spelling of 646511 in words is "six hundred forty-six thousand, five hundred eleven".