643647312 has 120 divisors (see below), whose sum is σ = 2245838400. Its totient is φ = 167178240.

The previous prime is 643647311. The next prime is 643647331. The reversal of 643647312 is 213746346.

It is a happy number.

643647312 is a `hidden beast` number, since 6 + 4 + 3 + 647 + 3 + 1 + 2 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643647311) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17937 + ... + 40112.

It is an arithmetic number, because the mean of its divisors is an integer number (18715320).

Almost surely, 2^643647312 is an apocalyptic number.

It is an amenable number.

643647312 is an abundant number, since it is smaller than the sum of its proper divisors (1602191088).

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

643647312 is a wasteful number, since it uses less digits than its factorization.

643647312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58081 (or 58072 counting only the distinct ones).

The product of its digits is 72576, while the sum is 36.

The square root of 643647312 is about 25370.2052021658. The cubic root of 643647312 is about 863.4078375532.

The spelling of 643647312 in words is "six hundred forty-three million, six hundred forty-seven thousand, three hundred twelve".