648569209 has 2 divisors, whose sum is σ = 648569210. Its totient is φ = 648569208.

The previous prime is 648569183. The next prime is 648569219. The reversal of 648569209 is 902965846.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 390260025 + 258309184 = 19755^2 + 16072^2 .

It is a cyclic number.

It is not a de Polignac number, because 648569209 - 2¹⁹ = 648044921 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (648569219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324284604 + 324284605.

It is an arithmetic number, because the mean of its divisors is an integer number (324284605).

Almost surely, 2^648569209 is an apocalyptic number.

It is an amenable number.

648569209 is a deficient number, since it is larger than the sum of its proper divisors (1).

648569209 is an equidigital number, since it uses as much as digits as its factorization.

648569209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 933120, while the sum is 49.

The square root of 648569209 is about 25467.0219892315. The cubic root of 648569209 is about 865.6030450174.

The spelling of 648569209 in words is "six hundred forty-eight million, five hundred sixty-nine thousand, two hundred nine".