643116022621 has 4 divisors (see below), whose sum is σ = 643482890332. Its totient is φ = 642749154912.

The previous prime is 643116022583. The next prime is 643116022631. The reversal of 643116022621 is 126220611346.

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 6168374521 + 636947648100 = 78539^2 + 798090^2 .

It is a cyclic number.

It is not a de Polignac number, because 643116022621 - 2¹⁷ = 643115891549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643116022631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 183431226 + ... + 183434731.

It is an arithmetic number, because the mean of its divisors is an integer number (160870722583).

Almost surely, 2^643116022621 is an apocalyptic number.

It is an amenable number.

643116022621 is a deficient number, since it is larger than the sum of its proper divisors (366867711).

643116022621 is a wasteful number, since it uses less digits than its factorization.

643116022621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366867710.

The product of its (nonzero) digits is 20736, while the sum is 34.

Adding to 643116022621 its reverse (126220611346), we get a palindrome (769336633967).

The spelling of 643116022621 in words is "six hundred forty-three billion, one hundred sixteen million, twenty-two thousand, six hundred twenty-one".