643228992 has 224 divisors, whose sum is σ = 2215530240. Its totient is φ = 179159040.

The previous prime is 643228939. The next prime is 643228997. The reversal of 643228992 is 299822346.

It is a tau number, because it is divible by the number of its divisors (224).

It is a super-2 number, since 2×643228992² = 827487072298672128, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643228997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 495288 + ... + 496584.

It is an arithmetic number, because the mean of its divisors is an integer number (9890760).

Almost surely, 2^643228992 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 643228992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1107765120).

643228992 is an abundant number, since it is smaller than the sum of its proper divisors (1572301248).

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

643228992 is a wasteful number, since it uses less digits than its factorization.

643228992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1366 (or 1350 counting only the distinct ones).

The product of its digits is 373248, while the sum is 45.

The square root of 643228992 is about 25361.9595457449. The cubic root of 643228992 is about 863.2207480118.

It can be divided in two parts, 6 and 43228992, that multiplied together give a palindrome (259373952).

The spelling of 643228992 in words is "six hundred forty-three million, two hundred twenty-eight thousand, nine hundred ninety-two".