645967 has 6 divisors (see below), whose sum is σ = 751488. Its totient is φ = 553644.

The previous prime is 645941. The next prime is 645973. The reversal of 645967 is 769546.

It is not a de Polignac number, because 645967 - 2⁷ = 645839 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 (645907) 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 5 ways as a sum of consecutive naturals, for example, 6543 + ... + 6640.

It is an arithmetic number, because the mean of its divisors is an integer number (125248).

2⁶⁴⁵⁹⁶⁷ is an apocalyptic number.

645967 is a deficient number, since it is larger than the sum of its proper divisors (105521).

645967 is a wasteful number, since it uses less digits than its factorization.

645967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13197 (or 13190 counting only the distinct ones).

The product of its digits is 45360, while the sum is 37.

The square root of 645967 is about 803.7207226394. The cubic root of 645967 is about 86.4443827042. Note that the first 3 decimals are identical.

The spelling of 645967 in words is "six hundred forty-five thousand, nine hundred sixty-seven".