643602780 has 96 divisors (see below), whose sum is σ = 2066964480. Its totient is φ = 166086720.

The previous prime is 643602769. The next prime is 643602851. The reversal of 643602780 is 87206346.

643602780 is a `hidden beast` number, since 6 + 43 + 602 + 7 + 8 + 0 = 666.

643602780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2484 + ... + 35963.

It is an arithmetic number, because the mean of its divisors is an integer number (21530880).

Almost surely, 2^643602780 is an apocalyptic number.

643602780 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 643602780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1033482240).

643602780 is an abundant number, since it is smaller than the sum of its proper divisors (1423361700).

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

643602780 is a wasteful number, since it uses less digits than its factorization.

643602780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38496 (or 38488 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 643602780 is about 25369.3275433150. The cubic root of 643602780 is about 863.3879249065.

The spelling of 643602780 in words is "six hundred forty-three million, six hundred two thousand, seven hundred eighty".