647218427 has 2 divisors, whose sum is σ = 647218428. Its totient is φ = 647218426.

The previous prime is 647218421. The next prime is 647218447. The reversal of 647218427 is 724812746.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 647218427 - 2¹⁸ = 646956283 is a prime.

It is not a weakly prime, because it can be changed into another prime (647218421) 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 as a sum of consecutive naturals, namely, 323609213 + 323609214.

It is an arithmetic number, because the mean of its divisors is an integer number (323609214).

Almost surely, 2^647218427 is an apocalyptic number.

647218427 is a deficient number, since it is larger than the sum of its proper divisors (1).

647218427 is an equidigital number, since it uses as much as digits as its factorization.

647218427 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 150528, while the sum is 41.

The square root of 647218427 is about 25440.4879473645. The cubic root of 647218427 is about 865.0016937831.

The spelling of 647218427 in words is "six hundred forty-seven million, two hundred eighteen thousand, four hundred twenty-seven".