667645 has 16 divisors (see below), whose sum is σ = 892800. Its totient is φ = 475200.

The previous prime is 667643. The next prime is 667649. The reversal of 667645 is 546766.

It is not a de Polignac number, because 667645 - 2¹ = 667643 is a prime.

667645 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 667645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3256 + ... + 3454.

It is an arithmetic number, because the mean of its divisors is an integer number (55800).

2⁶⁶⁷⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

667645 is a deficient number, since it is larger than the sum of its proper divisors (225155).

667645 is a wasteful number, since it uses less digits than its factorization.

667645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276.

The product of its digits is 30240, while the sum is 34.

The square root of 667645 is about 817.0954656587. The cubic root of 667645 is about 87.4007582317.

The spelling of 667645 in words is "six hundred sixty-seven thousand, six hundred forty-five".