64644662889 has 12 divisors (see below), whose sum is σ = 93378828036. Its totient is φ = 43094963232.

The previous prime is 64644662869. The next prime is 64644662899. The reversal of 64644662889 is 98826644646.

It can be written as a sum of positive squares in 2 ways, for example, as 48646713600 + 15997949289 = 220560^2 + 126483^2 .

It is not a de Polignac number, because 64644662889 - 2⁸ = 64644662633 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (64644662869) 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 in 11 ways as a sum of consecutive naturals, for example, 197619 + ... + 410295.

It is an arithmetic number, because the mean of its divisors is an integer number (7781569003).

Almost surely, 2^64644662889 is an apocalyptic number.

It is an amenable number.

64644662889 is a deficient number, since it is larger than the sum of its proper divisors (28734165147).

64644662889 is a wasteful number, since it uses less digits than its factorization.

64644662889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246456 (or 246453 counting only the distinct ones).

The product of its digits is 95551488, while the sum is 63.

The spelling of 64644662889 in words is "sixty-four billion, six hundred forty-four million, six hundred sixty-two thousand, eight hundred eighty-nine".