648642257 has 2 divisors, whose sum is σ = 648642258. Its totient is φ = 648642256.

The previous prime is 648642223. The next prime is 648642287. The reversal of 648642257 is 752246846.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 427703761 + 220938496 = 20681^2 + 14864^2 .

It is a cyclic number.

It is not a de Polignac number, because 648642257 - 2¹² = 648638161 is a prime.

It is not a weakly prime, because it can be changed into another prime (648642287) 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, 324321128 + 324321129.

It is an arithmetic number, because the mean of its divisors is an integer number (324321129).

Almost surely, 2^648642257 is an apocalyptic number.

It is an amenable number.

648642257 is a deficient number, since it is larger than the sum of its proper divisors (1).

648642257 is an equidigital number, since it uses as much as digits as its factorization.

648642257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 645120, while the sum is 44.

The square root of 648642257 is about 25468.4561173229. The cubic root of 648642257 is about 865.6355412654.

The spelling of 648642257 in words is "six hundred forty-eight million, six hundred forty-two thousand, two hundred fifty-seven".