646399 has 8 divisors (see below), whose sum is σ = 733040. Its totient is φ = 565056.

The previous prime is 646397. The next prime is 646403. The reversal of 646399 is 993646.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 646399 - 2¹ = 646397 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 (646397) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1062 + ... + 1555.

It is an arithmetic number, because the mean of its divisors is an integer number (91630).

2⁶⁴⁶³⁹⁹ is an apocalyptic number.

646399 is a deficient number, since it is larger than the sum of its proper divisors (86641).

646399 is a wasteful number, since it uses less digits than its factorization.

646399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2649.

The product of its digits is 34992, while the sum is 37.

The square root of 646399 is about 803.9894277912. The cubic root of 646399 is about 86.4636487305.

The spelling of 646399 in words is "six hundred forty-six thousand, three hundred ninety-nine".