646900 has 18 divisors (see below), whose sum is σ = 1403990. Its totient is φ = 258720.

The previous prime is 646897. The next prime is 646909. The reversal of 646900 is 9646.

It can be written as a sum of positive squares in 3 ways, for example, as 484 + 646416 = 22^2 + 804^2 .

It is a super-2 number, since 2×646900² = 836959220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646909) 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 5 ways as a sum of consecutive naturals, for example, 3135 + ... + 3334.

2⁶⁴⁶⁹⁰⁰ is an apocalyptic number.

It is an amenable number.

646900 is an abundant number, since it is smaller than the sum of its proper divisors (757090).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646900 is a wasteful number, since it uses less digits than its factorization.

646900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6483 (or 6476 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 646900 is about 804.3009387039. The cubic root of 646900 is about 86.4859812224.

The spelling of 646900 in words is "six hundred forty-six thousand, nine hundred".