643476428 has 72 divisors (see below), whose sum is σ = 1374156000. Its totient is φ = 262386432.

The previous prime is 643476419. The next prime is 643476437. The reversal of 643476428 is 824674346.

It is an interprime number because it is at equal distance from previous prime (643476419) and next prime (643476437).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1573088 + ... + 1573496.

It is an arithmetic number, because the mean of its divisors is an integer number (19085500).

Almost surely, 2^643476428 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643476428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (687078000).

643476428 is an abundant number, since it is smaller than the sum of its proper divisors (730679572).

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

643476428 is a wasteful number, since it uses less digits than its factorization.

643476428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 799 (or 790 counting only the distinct ones).

The product of its digits is 774144, while the sum is 44.

The square root of 643476428 is about 25366.8371698168. The cubic root of 643476428 is about 863.3314211466.

The spelling of 643476428 in words is "six hundred forty-three million, four hundred seventy-six thousand, four hundred twenty-eight".