667439647 has 4 divisors (see below), whose sum is σ = 762788176. Its totient is φ = 572091120.

The previous prime is 667439609. The next prime is 667439659. The reversal of 667439647 is 746934766.

667439647 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667439647 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 667439594 and 667439603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667439677) 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, 47674254 + ... + 47674267.

It is an arithmetic number, because the mean of its divisors is an integer number (190697044).

Almost surely, 2^667439647 is an apocalyptic number.

667439647 is a deficient number, since it is larger than the sum of its proper divisors (95348529).

667439647 is an equidigital number, since it uses as much as digits as its factorization.

667439647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95348528.

The product of its digits is 4572288, while the sum is 52.

The square root of 667439647 is about 25834.8533380780. The cubic root of 667439647 is about 873.9179645889.

The spelling of 667439647 in words is "six hundred sixty-seven million, four hundred thirty-nine thousand, six hundred forty-seven".