8644021918 has 32 divisors (see below), whose sum is σ = 16019827200. Its totient is φ = 3414744864.

The previous prime is 8644021913. The next prime is 8644021993. The reversal of 8644021918 is 8191204468.

It is a super-2 number, since 2×8644021918² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8644021913) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 429298 + ... + 448981.

It is an arithmetic number, because the mean of its divisors is an integer number (500619600).

Almost surely, 2^8644021918 is an apocalyptic number.

8644021918 is a deficient number, since it is larger than the sum of its proper divisors (7375805282).

8644021918 is a wasteful number, since it uses less digits than its factorization.

8644021918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878344.

The product of its (nonzero) digits is 110592, while the sum is 43.

The square root of 8644021918 is about 92973.2322660668. The cubic root of 8644021918 is about 2052.2894839831.

The spelling of 8644021918 in words is "eight billion, six hundred forty-four million, twenty-one thousand, nine hundred eighteen".