643402100 has 36 divisors (see below), whose sum is σ = 1523110848. Its totient is φ = 233964000.

The previous prime is 643402099. The next prime is 643402121. The reversal of 643402100 is 1204346.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 291356 + ... + 293555.

Almost surely, 2^643402100 is an apocalyptic number.

It is an amenable number.

643402100 is an abundant number, since it is smaller than the sum of its proper divisors (879708748).

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

643402100 is a wasteful number, since it uses less digits than its factorization.

643402100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 584936 (or 584929 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 643402100 is about 25365.3720650812. The cubic root of 643402100 is about 863.2981787123.

Adding to 643402100 its reverse (1204346), we get a palindrome (644606446).

The spelling of 643402100 in words is "six hundred forty-three million, four hundred two thousand, one hundred".