643351334551 has 4 divisors (see below), whose sum is σ = 645294994504. Its totient is φ = 641407674600.

The previous prime is 643351334543. The next prime is 643351334569. The reversal of 643351334551 is 155433153346.

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

It is a cyclic number.

It is not a de Polignac number, because 643351334551 - 2³ = 643351334543 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643351334498 and 643351334507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643351304551) 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, 971829480 + ... + 971830141.

It is an arithmetic number, because the mean of its divisors is an integer number (161323748626).

Almost surely, 2^643351334551 is an apocalyptic number.

643351334551 is a deficient number, since it is larger than the sum of its proper divisors (1943659953).

643351334551 is a wasteful number, since it uses less digits than its factorization.

643351334551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1943659952.

The product of its digits is 972000, while the sum is 43.

Adding to 643351334551 its reverse (155433153346), we get a palindrome (798784487897).

The spelling of 643351334551 in words is "six hundred forty-three billion, three hundred fifty-one million, three hundred thirty-four thousand, five hundred fifty-one".