646985 has 8 divisors (see below), whose sum is σ = 786240. Its totient is φ = 511024.

The previous prime is 646981. The next prime is 646991. The reversal of 646985 is 589646.

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 646985 - 2² = 646981 is a prime.

It is a nialpdrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 646985.

It is not an unprimeable number, because it can be changed into a prime (646981) 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, 365 + ... + 1194.

It is an arithmetic number, because the mean of its divisors is an integer number (98280).

2⁶⁴⁶⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

646985 is a deficient number, since it is larger than the sum of its proper divisors (139255).

646985 is a wasteful number, since it uses less digits than its factorization.

646985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1647.

The product of its digits is 51840, while the sum is 38.

The square root of 646985 is about 804.3537778863. The cubic root of 646985 is about 86.4897690240.

The spelling of 646985 in words is "six hundred forty-six thousand, nine hundred eighty-five".