667904 has 18 divisors (see below), whose sum is σ = 1333710. Its totient is φ = 333824.

The previous prime is 667903. The next prime is 667921. The reversal of 667904 is 409766.

It can be written as a sum of positive squares in only one way, i.e., 565504 + 102400 = 752^2 + 320^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an Ulam number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (667903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1049 + ... + 1560.

It is an arithmetic number, because the mean of its divisors is an integer number (74095).

2⁶⁶⁷⁹⁰⁴ is an apocalyptic number.

667904 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

667904 is a deficient number, since it is larger than the sum of its proper divisors (665806).

667904 is an equidigital number, since it uses as much as digits as its factorization.

667904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2625 (or 2611 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 667904 is about 817.2539385038. The cubic root of 667904 is about 87.4120585833.

The spelling of 667904 in words is "six hundred sixty-seven thousand, nine hundred four".