666631001 has 4 divisors (see below), whose sum is σ = 671880192. Its totient is φ = 661381812.

The previous prime is 666630983. The next prime is 666631019. The reversal of 666631001 is 100136666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (666630983) and next prime (666631019).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666631001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666631051) 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, 2624405 + ... + 2624658.

It is an arithmetic number, because the mean of its divisors is an integer number (167970048).

Almost surely, 2^666631001 is an apocalyptic number.

It is an amenable number.

666631001 is a deficient number, since it is larger than the sum of its proper divisors (5249191).

666631001 is a wasteful number, since it uses less digits than its factorization.

666631001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5249190.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 666631001 is about 25819.1983028134. The cubic root of 666631001 is about 873.5648860437.

Adding to 666631001 its reverse (100136666), we get a palindrome (766767667).

The spelling of 666631001 in words is "six hundred sixty-six million, six hundred thirty-one thousand, one".