4000644864 has 288 divisors, whose sum is σ = 12774182400. Its totient is φ = 1230888960.

The previous prime is 4000644821. The next prime is 4000644877. The reversal of 4000644864 is 4684460004.

4000644864 is a `hidden beast` number, since 4 + 0 + 0 + 0 + 644 + 8 + 6 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5384077 + ... + 5384819.

It is an arithmetic number, because the mean of its divisors is an integer number (44354800).

Almost surely, 2^4000644864 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 4000644864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6387091200).

4000644864 is an abundant number, since it is smaller than the sum of its proper divisors (8773537536).

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

4000644864 is a wasteful number, since it uses less digits than its factorization.

4000644864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 828 (or 808 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 36.

The square root of 4000644864 is about 63250.6510954630. The cubic root of 4000644864 is about 1587.4863522004.

The spelling of 4000644864 in words is "four billion, six hundred forty-four thousand, eight hundred sixty-four".