667428 has 12 divisors (see below), whose sum is σ = 1557360. Its totient is φ = 222472.

The previous prime is 667427. The next prime is 667441. The reversal of 667428 is 824766.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (667421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27798 + ... + 27821.

It is an arithmetic number, because the mean of its divisors is an integer number (129780).

2⁶⁶⁷⁴²⁸ is an apocalyptic number.

It is an amenable number.

667428 is an abundant number, since it is smaller than the sum of its proper divisors (889932).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

667428 is a wasteful number, since it uses less digits than its factorization.

667428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55626 (or 55624 counting only the distinct ones).

The product of its digits is 16128, while the sum is 33.

The square root of 667428 is about 816.9626674457. The cubic root of 667428 is about 87.3912881192.

The spelling of 667428 in words is "six hundred sixty-seven thousand, four hundred twenty-eight".