646744 has 16 divisors (see below), whose sum is σ = 1386000. Its totient is φ = 277152.

The previous prime is 646721. The next prime is 646757. The reversal of 646744 is 447646.

It is a nialpdrome in base 15.

It is a congruent number.

It is an unprimeable number.

646744 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 in 3 ways as a sum of consecutive naturals, for example, 5719 + ... + 5830.

It is an arithmetic number, because the mean of its divisors is an integer number (86625).

2⁶⁴⁶⁷⁴⁴ is an apocalyptic number.

It is an amenable number.

646744 is an abundant number, since it is smaller than the sum of its proper divisors (739256).

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

646744 is a wasteful number, since it uses less digits than its factorization.

646744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11562 (or 11558 counting only the distinct ones).

The product of its digits is 16128, while the sum is 31.

The square root of 646744 is about 804.2039542305. The cubic root of 646744 is about 86.4790286292.

The spelling of 646744 in words is "six hundred forty-six thousand, seven hundred forty-four".