643642272 has 288 divisors, whose sum is σ = 2311545600. Its totient is φ = 165335040.

The previous prime is 643642261. The next prime is 643642289. The reversal of 643642272 is 272246346.

643642272 is a `hidden beast` number, since 6 + 4 + 3 + 642 + 2 + 7 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1074229 + ... + 1074827.

It is an arithmetic number, because the mean of its divisors is an integer number (8026200).

Almost surely, 2^643642272 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 643642272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1155772800).

643642272 is an abundant number, since it is smaller than the sum of its proper divisors (1667903328).

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

643642272 is a wasteful number, since it uses less digits than its factorization.

643642272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 676 (or 665 counting only the distinct ones).

The product of its digits is 96768, while the sum is 36.

The square root of 643642272 is about 25370.1058728575. The cubic root of 643642272 is about 863.4055839449.

The spelling of 643642272 in words is "six hundred forty-three million, six hundred forty-two thousand, two hundred seventy-two".