646390 has 16 divisors (see below), whose sum is σ = 1195632. Its totient is φ = 251424.

The previous prime is 646379. The next prime is 646397. The reversal of 646390 is 93646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646397) 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 7 ways as a sum of consecutive naturals, for example, 504 + ... + 1243.

It is an arithmetic number, because the mean of its divisors is an integer number (74727).

2⁶⁴⁶³⁹⁰ is an apocalyptic number.

646390 is a deficient number, since it is larger than the sum of its proper divisors (549242).

646390 is a wasteful number, since it uses less digits than its factorization.

646390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1791.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 646390 is about 803.9838306832. The cubic root of 646390 is about 86.4632474425.

The spelling of 646390 in words is "six hundred forty-six thousand, three hundred ninety".