8644021920 has 480 divisors, whose sum is σ = 32562528768. Its totient is φ = 2154442752.

The previous prime is 8644021913. The next prime is 8644021993. The reversal of 8644021920 is 291204468.

8644021920 is a `hidden beast` number, since 8 + 64 + 402 + 192 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a super-2 number, since 2×8644021920² (a number of 21 digits) contains 22 as substring.

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

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 79 ways as a sum of consecutive naturals, for example, 14009452 + ... + 14010068.

Almost surely, 2^8644021920 is an apocalyptic number.

8644021920 is a gapful number since it is divisible by the number (80) 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 8644021920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16281264384).

8644021920 is an abundant number, since it is smaller than the sum of its proper divisors (23918506848).

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

8644021920 is a wasteful number, since it uses less digits than its factorization.

8644021920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 714 (or 697 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 8644021920 is about 92973.2322768226. The cubic root of 8644021920 is about 2052.2894841414.

The spelling of 8644021920 in words is "eight billion, six hundred forty-four million, twenty-one thousand, nine hundred twenty".