643617504 has 72 divisors (see below), whose sum is σ = 1849236480. Its totient is φ = 212318208.

The previous prime is 643617497. The next prime is 643617509. The reversal of 643617504 is 405716346.

It is a happy number.

643617504 is a `hidden beast` number, since 643 + 6 + 1 + 7 + 5 + 0 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643617509) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16417 + ... + 39455.

It is an arithmetic number, because the mean of its divisors is an integer number (25683840).

Almost surely, 2^643617504 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643617504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (924618240).

643617504 is an abundant number, since it is smaller than the sum of its proper divisors (1205618976).

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

643617504 is a wasteful number, since it uses less digits than its factorization.

643617504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23152 (or 23141 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 643617504 is about 25369.6177346053. The cubic root of 643617504 is about 863.3945088986.

The spelling of 643617504 in words is "six hundred forty-three million, six hundred seventeen thousand, five hundred four".