666651567 has 4 divisors (see below), whose sum is σ = 888868760. Its totient is φ = 444434376.

The previous prime is 666651551. The next prime is 666651569. The reversal of 666651567 is 765156666.

It is a happy number.

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

It is not a de Polignac number, because 666651567 - 2⁴ = 666651551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666651569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111108592 + ... + 111108597.

It is an arithmetic number, because the mean of its divisors is an integer number (222217190).

Almost surely, 2^666651567 is an apocalyptic number.

666651567 is a deficient number, since it is larger than the sum of its proper divisors (222217193).

666651567 is a wasteful number, since it uses less digits than its factorization.

666651567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222217192.

The product of its digits is 1360800, while the sum is 48.

The square root of 666651567 is about 25819.5965692727. The cubic root of 666651567 is about 873.5738692996.

The spelling of 666651567 in words is "six hundred sixty-six million, six hundred fifty-one thousand, five hundred sixty-seven".