667545640 has 32 divisors (see below), whose sum is σ = 1502721000. Its totient is φ = 266886144.

The previous prime is 667545623. The next prime is 667545643. The reversal of 667545640 is 46545766.

It is a happy number.

667545640 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 181872196 + 485673444 = 13486^2 + 22038^2 .

It is not an unprimeable number, because it can be changed into a prime (667545643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 138796 + ... + 143524.

Almost surely, 2^667545640 is an apocalyptic number.

It is an amenable number.

667545640 is an abundant number, since it is smaller than the sum of its proper divisors (835175360).

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

667545640 is a wasteful number, since it uses less digits than its factorization.

667545640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8269 (or 8265 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 43.

The square root of 667545640 is about 25836.9046133626. The cubic root of 667545640 is about 873.9642230955.

The spelling of 667545640 in words is "six hundred sixty-seven million, five hundred forty-five thousand, six hundred forty".