643022820 has 192 divisors, whose sum is σ = 2205665280. Its totient is φ = 154224000.

The previous prime is 643022767. The next prime is 643022837. The reversal of 643022820 is 28220346.

643022820 is a `hidden beast` number, since 6 + 430 + 228 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 611295 + ... + 612345.

It is an arithmetic number, because the mean of its divisors is an integer number (11487840).

Almost surely, 2^643022820 is an apocalyptic number.

643022820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643022820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1102832640).

643022820 is an abundant number, since it is smaller than the sum of its proper divisors (1562642460).

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

643022820 is a wasteful number, since it uses less digits than its factorization.

643022820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1183 (or 1175 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 643022820 is about 25357.8946286950. The cubic root of 643022820 is about 863.1285097532.

The spelling of 643022820 in words is "six hundred forty-three million, twenty-two thousand, eight hundred twenty".