64688209 has 2 divisors, whose sum is σ = 64688210. Its totient is φ = 64688208.

The previous prime is 64688191. The next prime is 64688219. The reversal of 64688209 is 90288646.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 36300625 + 28387584 = 6025^2 + 5328^2 .

It is a cyclic number.

It is not a de Polignac number, because 64688209 - 2⁷ = 64688081 is a prime.

It is not a weakly prime, because it can be changed into another prime (64688219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32344104 + 32344105.

It is an arithmetic number, because the mean of its divisors is an integer number (32344105).

Almost surely, 2^64688209 is an apocalyptic number.

It is an amenable number.

64688209 is a deficient number, since it is larger than the sum of its proper divisors (1).

64688209 is an equidigital number, since it uses as much as digits as its factorization.

64688209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 64688209 is about 8042.8980473459. The cubic root of 64688209 is about 401.4286600015.

The spelling of 64688209 in words is "sixty-four million, six hundred eighty-eight thousand, two hundred nine".