648405217 has 2 divisors, whose sum is σ = 648405218. Its totient is φ = 648405216.

The previous prime is 648405193. The next prime is 648405239. The reversal of 648405217 is 712504846.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 449482401 + 198922816 = 21201^2 + 14104^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-648405217 is a prime.

It is not a weakly prime, because it can be changed into another prime (648405617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324202608 + 324202609.

It is an arithmetic number, because the mean of its divisors is an integer number (324202609).

Almost surely, 2^648405217 is an apocalyptic number.

It is an amenable number.

648405217 is a deficient number, since it is larger than the sum of its proper divisors (1).

648405217 is an equidigital number, since it uses as much as digits as its factorization.

648405217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 53760, while the sum is 37.

The square root of 648405217 is about 25463.8020923820. The cubic root of 648405217 is about 865.5300823901.

The spelling of 648405217 in words is "six hundred forty-eight million, four hundred five thousand, two hundred seventeen".