64944618561 has 16 divisors (see below), whose sum is σ = 101278158400. Its totient is φ = 41017653504.

The previous prime is 64944618539. The next prime is 64944618701. The reversal of 64944618561 is 16581644946.

64944618561 is a `hidden beast` number, since 6 + 49 + 4 + 461 + 85 + 61 = 666.

It is not a de Polignac number, because 64944618561 - 2¹⁸ = 64944356417 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 64944618498 and 64944618507.

It is not an unprimeable number, because it can be changed into a prime (64944618511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63298336 + ... + 63299361.

It is an arithmetic number, because the mean of its divisors is an integer number (6329884900).

Almost surely, 2^64944618561 is an apocalyptic number.

It is an amenable number.

64944618561 is a deficient number, since it is larger than the sum of its proper divisors (36333539839).

64944618561 is a wasteful number, since it uses less digits than its factorization.

64944618561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126597725 (or 126597719 counting only the distinct ones).

The product of its digits is 4976640, while the sum is 54.

The spelling of 64944618561 in words is "sixty-four billion, nine hundred forty-four million, six hundred eighteen thousand, five hundred sixty-one".