643123120 has 40 divisors (see below), whose sum is σ = 1500127200. Its totient is φ = 256412160.

The previous prime is 643123099. The next prime is 643123127. The reversal of 643123120 is 21321346.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 643123091 and 643123100.

It is not an unprimeable number, because it can be changed into a prime (643123127) 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, 11956 + ... + 37804.

It is an arithmetic number, because the mean of its divisors is an integer number (37503180).

Almost surely, 2^643123120 is an apocalyptic number.

It is an amenable number.

643123120 is an abundant number, since it is smaller than the sum of its proper divisors (857004080).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643123120 is a wasteful number, since it uses less digits than its factorization.

643123120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26173 (or 26167 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 643123120 is about 25359.8722394258. The cubic root of 643123120 is about 863.1733849303.

Adding to 643123120 its reverse (21321346), we get a palindrome (664444466).

The spelling of 643123120 in words is "six hundred forty-three million, one hundred twenty-three thousand, one hundred twenty".