646868 has 6 divisors (see below), whose sum is σ = 1132026. Its totient is φ = 323432.

The previous prime is 646859. The next prime is 646873. The reversal of 646868 is 868646.

It can be written as a sum of positive squares in only one way, i.e., 611524 + 35344 = 782^2 + 188^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80855 + ... + 80862.

It is an arithmetic number, because the mean of its divisors is an integer number (188671).

2⁶⁴⁶⁸⁶⁸ is an apocalyptic number.

It is an amenable number.

646868 is a deficient number, since it is larger than the sum of its proper divisors (485158).

646868 is a wasteful number, since it uses less digits than its factorization.

646868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161721 (or 161719 counting only the distinct ones).

The product of its digits is 55296, while the sum is 38.

The square root of 646868 is about 804.2810454064. The cubic root of 646868 is about 86.4845551406.

The spelling of 646868 in words is "six hundred forty-six thousand, eight hundred sixty-eight".