643244054545 has 4 divisors (see below), whose sum is σ = 771892865460. Its totient is φ = 514595243632.

The previous prime is 643244054533. The next prime is 643244054587. The reversal of 643244054545 is 545450442346.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 503594606736 + 139649447809 = 709644^2 + 373697^2 .

It is a cyclic number.

It is not a de Polignac number, because 643244054545 - 2⁵ = 643244054513 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643244054495 and 643244054504.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64324405450 + ... + 64324405459.

It is an arithmetic number, because the mean of its divisors is an integer number (192973216365).

Almost surely, 2^643244054545 is an apocalyptic number.

It is an amenable number.

643244054545 is a deficient number, since it is larger than the sum of its proper divisors (128648810915).

643244054545 is a wasteful number, since it uses less digits than its factorization.

643244054545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128648810914.

The product of its (nonzero) digits is 4608000, while the sum is 46.

The spelling of 643244054545 in words is "six hundred forty-three billion, two hundred forty-four million, fifty-four thousand, five hundred forty-five".