643613616 has 60 divisors (see below), whose sum is σ = 1808857440. Its totient is φ = 213628800.

The previous prime is 643613587. The next prime is 643613627. The reversal of 643613616 is 616316346.

643613616 is a `hidden beast` number, since 6 + 4 + 36 + 1 + 3 + 616 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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 an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25066 + ... + 43766.

It is an arithmetic number, because the mean of its divisors is an integer number (30147624).

Almost surely, 2^643613616 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 643613616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (904428720).

643613616 is an abundant number, since it is smaller than the sum of its proper divisors (1165243824).

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

643613616 is a wasteful number, since it uses less digits than its factorization.

643613616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18954 (or 18945 counting only the distinct ones).

The product of its digits is 46656, while the sum is 36.

The square root of 643613616 is about 25369.5411073988. The cubic root of 643613616 is about 863.3927703481.

The spelling of 643613616 in words is "six hundred forty-three million, six hundred thirteen thousand, six hundred sixteen".