643958418420 has 144 divisors (see below), whose sum is σ = 1968066172800. Its totient is φ = 170429591808.

The previous prime is 643958418419. The next prime is 643958418421. The reversal of 643958418420 is 24814859346.

643958418420 is a `hidden beast` number, since 6 + 4 + 3 + 9 + 584 + 18 + 42 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (643958418419) and next prime (643958418421).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643958418421) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 34937247 + ... + 34955673.

It is an arithmetic number, because the mean of its divisors is an integer number (13667126200).

Almost surely, 2^643958418420 is an apocalyptic number.

643958418420 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 643958418420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (984033086400).

643958418420 is an abundant number, since it is smaller than the sum of its proper divisors (1324107754380).

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

643958418420 is a wasteful number, since it uses less digits than its factorization.

643958418420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19894 (or 19889 counting only the distinct ones).

The product of its (nonzero) digits is 6635520, while the sum is 54.

The spelling of 643958418420 in words is "six hundred forty-three billion, nine hundred fifty-eight million, four hundred eighteen thousand, four hundred twenty".