64491001609 has 2 divisors, whose sum is σ = 64491001610. Its totient is φ = 64491001608.

The previous prime is 64491001571. The next prime is 64491001651. The reversal of 64491001609 is 90610019446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37349427600 + 27141574009 = 193260^2 + 164747^2 .

It is a cyclic number.

It is not a de Polignac number, because 64491001609 - 2⁹ = 64491001097 is a prime.

It is not a weakly prime, because it can be changed into another prime (64491004609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32245500804 + 32245500805.

It is an arithmetic number, because the mean of its divisors is an integer number (32245500805).

Almost surely, 2^64491001609 is an apocalyptic number.

It is an amenable number.

64491001609 is a deficient number, since it is larger than the sum of its proper divisors (1).

64491001609 is an equidigital number, since it uses as much as digits as its factorization.

64491001609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46656, while the sum is 40.

The spelling of 64491001609 in words is "sixty-four billion, four hundred ninety-one million, one thousand, six hundred nine".