646997 has 8 divisors (see below), whose sum is σ = 703416. Its totient is φ = 591552.

The previous prime is 646993. The next prime is 647011. The reversal of 646997 is 799646.

It can be written as a sum of positive squares in 4 ways, for example, as 21316 + 625681 = 146^2 + 791^2 .

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

It is not a de Polignac number, because 646997 - 2² = 646993 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646991) 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, 1883 + ... + 2199.

It is an arithmetic number, because the mean of its divisors is an integer number (87927).

2⁶⁴⁶⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

646997 is a deficient number, since it is larger than the sum of its proper divisors (56419).

646997 is a wasteful number, since it uses less digits than its factorization.

646997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 487.

The product of its digits is 81648, while the sum is 41.

The square root of 646997 is about 804.3612372560. The cubic root of 646997 is about 86.4903037457.

The spelling of 646997 in words is "six hundred forty-six thousand, nine hundred ninety-seven".