643243121353 has 4 divisors (see below), whose sum is σ = 735134995840. Its totient is φ = 551351246868.

The previous prime is 643243121243. The next prime is 643243121363. The reversal of 643243121353 is 353121342346.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 643243121353 - 2⁹ = 643243120841 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643243121363) 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, 45945937233 + ... + 45945937246.

It is an arithmetic number, because the mean of its divisors is an integer number (183783748960).

Almost surely, 2^643243121353 is an apocalyptic number.

It is an amenable number.

643243121353 is a deficient number, since it is larger than the sum of its proper divisors (91891874487).

643243121353 is an equidigital number, since it uses as much as digits as its factorization.

643243121353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91891874486.

The product of its digits is 155520, while the sum is 37.

Adding to 643243121353 its reverse (353121342346), we get a palindrome (996364463699).

The spelling of 643243121353 in words is "six hundred forty-three billion, two hundred forty-three million, one hundred twenty-one thousand, three hundred fifty-three".