643354740 has 144 divisors (see below), whose sum is σ = 2247178752. Its totient is φ = 145939968.

The previous prime is 643354721. The next prime is 643354771. The reversal of 643354740 is 47453346.

It is a happy number.

643354740 is a `hidden beast` number, since 643 + 3 + 5 + 4 + 7 + 4 + 0 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 643354695 and 643354704.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 170757 + ... + 174483.

It is an arithmetic number, because the mean of its divisors is an integer number (15605408).

Almost surely, 2^643354740 is an apocalyptic number.

643354740 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 643354740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1123589376).

643354740 is an abundant number, since it is smaller than the sum of its proper divisors (1603824012).

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

643354740 is a wasteful number, since it uses less digits than its factorization.

643354740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3886 (or 3881 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 36.

The square root of 643354740 is about 25364.4384917151. The cubic root of 643354740 is about 863.2769961035.

The spelling of 643354740 in words is "six hundred forty-three million, three hundred fifty-four thousand, seven hundred forty".