643994248543 has 8 divisors (see below), whose sum is σ = 654564866576. Its totient is φ = 633424060800.

The previous prime is 643994248529. The next prime is 643994248553. The reversal of 643994248543 is 345842499346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643994248543 - 2²¹ = 643992151391 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (61).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643994248553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4553728 + ... + 4693018.

It is an arithmetic number, because the mean of its divisors is an integer number (81820608322).

Almost surely, 2^643994248543 is an apocalyptic number.

643994248543 is a deficient number, since it is larger than the sum of its proper divisors (10570618033).

643994248543 is a wasteful number, since it uses less digits than its factorization.

643994248543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215145.

The product of its digits is 89579520, while the sum is 61.

The spelling of 643994248543 in words is "six hundred forty-three billion, nine hundred ninety-four million, two hundred forty-eight thousand, five hundred forty-three".