64561663643 has 32 divisors (see below), whose sum is σ = 70152264000. Its totient is φ = 59215380480.

The previous prime is 64561663633. The next prime is 64561663651. The reversal of 64561663643 is 34636616546.

64561663643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 64561663643 - 2¹⁴ = 64561647259 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 64561663591 and 64561663600.

It is not an unprimeable number, because it can be changed into a prime (64561663633) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 77878553 + ... + 77879381.

It is an arithmetic number, because the mean of its divisors is an integer number (2192258250).

Almost surely, 2^64561663643 is an apocalyptic number.

64561663643 is a deficient number, since it is larger than the sum of its proper divisors (5590600357).

64561663643 is a wasteful number, since it uses less digits than its factorization.

64561663643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1535.

The product of its digits is 5598720, while the sum is 50.

The spelling of 64561663643 in words is "sixty-four billion, five hundred sixty-one million, six hundred sixty-three thousand, six hundred forty-three".