667641563 has 2 divisors, whose sum is σ = 667641564. Its totient is φ = 667641562.

The previous prime is 667641529. The next prime is 667641593. The reversal of 667641563 is 365146766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 667641563 - 2⁸ = 667641307 is a prime.

It is not a weakly prime, because it can be changed into another prime (667641593) 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 as a sum of consecutive naturals, namely, 333820781 + 333820782.

It is an arithmetic number, because the mean of its divisors is an integer number (333820782).

Almost surely, 2^667641563 is an apocalyptic number.

667641563 is a deficient number, since it is larger than the sum of its proper divisors (1).

667641563 is an equidigital number, since it uses as much as digits as its factorization.

667641563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 544320, while the sum is 44.

The square root of 667641563 is about 25838.7608642520. The cubic root of 667641563 is about 874.0060825330.

The spelling of 667641563 in words is "six hundred sixty-seven million, six hundred forty-one thousand, five hundred sixty-three".