643505346 has 72 divisors (see below), whose sum is σ = 1538671680. Its totient is φ = 194222160.

The previous prime is 643505311. The next prime is 643505351.

643505346 is a `hidden beast` number, since 643 + 5 + 0 + 5 + 3 + 4 + 6 = 666.

643505346 is nontrivially palindromic in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 643505346.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 781491 + ... + 782313.

It is an arithmetic number, because the mean of its divisors is an integer number (21370440).

Almost surely, 2^643505346 is an apocalyptic number.

643505346 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 643505346, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (769335840).

643505346 is an abundant number, since it is smaller than the sum of its proper divisors (895166334).

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

643505346 is a wasteful number, since it uses less digits than its factorization.

643505346 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1212 (or 1198 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 36.

The square root of 643505346 is about 25367.4071595818. The cubic root of 643505346 is about 863.3443537333.

It can be divided in two parts, 64350 and 5346, that added together give a palindrome (69696).

The spelling of 643505346 in words is "six hundred forty-three million, five hundred five thousand, three hundred forty-six".