646969 has 8 divisors (see below), whose sum is σ = 721440. Its totient is φ = 576576.

The previous prime is 646957. The next prime is 646979. The reversal of 646969 is 969646.

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 646969 - 2⁵ = 646937 is a prime.

It is a super-2 number, since 2×646969² = 837137773922, which contains 22 as substring.

It is a Duffinian number.

646969 is a modest number, since divided by 969 gives 646 as remainder.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (646909) 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, 679 + ... + 1324.

It is an arithmetic number, because the mean of its divisors is an integer number (90180).

2⁶⁴⁶⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

646969 is a deficient number, since it is larger than the sum of its proper divisors (74471).

646969 is a wasteful number, since it uses less digits than its factorization.

646969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2039.

The product of its digits is 69984, while the sum is 40.

The square root of 646969 is about 804.3438319525. The cubic root of 646969 is about 86.4890560514.

The spelling of 646969 in words is "six hundred forty-six thousand, nine hundred sixty-nine".