643543121 has 8 divisors (see below), whose sum is σ = 693545664. Its totient is φ = 593611920.

The previous prime is 643543099. The next prime is 643543123. The reversal of 643543121 is 121345346.

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 643543121 - 2⁶ = 643543057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (643543123) 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, 1706 + ... + 35916.

It is an arithmetic number, because the mean of its divisors is an integer number (86693208).

Almost surely, 2^643543121 is an apocalyptic number.

It is an amenable number.

643543121 is a deficient number, since it is larger than the sum of its proper divisors (50002543).

643543121 is a wasteful number, since it uses less digits than its factorization.

643543121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35671.

The product of its digits is 8640, while the sum is 29.

The square root of 643543121 is about 25368.1517064212. The cubic root of 643543121 is about 863.3612467268.

Adding to 643543121 its reverse (121345346), we get a palindrome (764888467).

The spelling of 643543121 in words is "six hundred forty-three million, five hundred forty-three thousand, one hundred twenty-one".