643522740 has 192 divisors, whose sum is σ = 2116423680. Its totient is φ = 143078400.

The previous prime is 643522729. The next prime is 643522751. The reversal of 643522740 is 47225346.

It is an interprime number because it is at equal distance from previous prime (643522729) and next prime (643522751).

It is a congruent number.

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, 4261665 + ... + 4261815.

It is an arithmetic number, because the mean of its divisors is an integer number (11023040).

Almost surely, 2^643522740 is an apocalyptic number.

643522740 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 643522740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1058211840).

643522740 is an abundant number, since it is smaller than the sum of its proper divisors (1472900940).

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

643522740 is a wasteful number, since it uses less digits than its factorization.

643522740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382 (or 380 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 33.

The square root of 643522740 is about 25367.7499987681. The cubic root of 643522740 is about 863.3521324185.

The spelling of 643522740 in words is "six hundred forty-three million, five hundred twenty-two thousand, seven hundred forty".