667644928 has 22 divisors (see below), whose sum is σ = 1334639906. Its totient is φ = 333821952.

The previous prime is 667644919. The next prime is 667644937. The reversal of 667644928 is 829446766.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (667644919) and next prime (667644937).

It can be written as a sum of positive squares in only one way, i.e., 569872384 + 97772544 = 23872^2 + 9888^2 .

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 324975 + ... + 327022.

Almost surely, 2^667644928 is an apocalyptic number.

It is an amenable number.

667644928 is a deficient number, since it is larger than the sum of its proper divisors (666994978).

667644928 is an equidigital number, since it uses as much as digits as its factorization.

667644928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652017 (or 651999 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 52.

The square root of 667644928 is about 25838.8259795216. The cubic root of 667644928 is about 874.0075508985.

The spelling of 667644928 in words is "six hundred sixty-seven million, six hundred forty-four thousand, nine hundred twenty-eight".