667656551 has 4 divisors (see below), whose sum is σ = 675158400. Its totient is φ = 660154704.

The previous prime is 667656533. The next prime is 667656553. The reversal of 667656551 is 155656766.

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-667656551 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 667656496 and 667656505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667656553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3750791 + ... + 3750968.

It is an arithmetic number, because the mean of its divisors is an integer number (168789600).

Almost surely, 2^667656551 is an apocalyptic number.

667656551 is a deficient number, since it is larger than the sum of its proper divisors (7501849).

667656551 is an equidigital number, since it uses as much as digits as its factorization.

667656551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7501848.

The product of its digits is 1134000, while the sum is 47.

The square root of 667656551 is about 25839.0508920123. The cubic root of 667656551 is about 874.0126227216.

The spelling of 667656551 in words is "six hundred sixty-seven million, six hundred fifty-six thousand, five hundred fifty-one".