64631709809 has 2 divisors, whose sum is σ = 64631709810. Its totient is φ = 64631709808.

The previous prime is 64631709787. The next prime is 64631709823. The reversal of 64631709809 is 90890713646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40907085025 + 23724624784 = 202255^2 + 154028^2 .

It is a cyclic number.

It is not a de Polignac number, because 64631709809 - 2⁸ = 64631709553 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (64631709829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32315854904 + 32315854905.

It is an arithmetic number, because the mean of its divisors is an integer number (32315854905).

Almost surely, 2^64631709809 is an apocalyptic number.

It is an amenable number.

64631709809 is a deficient number, since it is larger than the sum of its proper divisors (1).

64631709809 is an equidigital number, since it uses as much as digits as its factorization.

64631709809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1959552, while the sum is 53.

The spelling of 64631709809 in words is "sixty-four billion, six hundred thirty-one million, seven hundred nine thousand, eight hundred nine".