8618181993 has 12 divisors (see below), whose sum is σ = 12450354228. Its totient is φ = 5744592000.

The previous prime is 8618181973. The next prime is 8618182031. The reversal of 8618181993 is 3991818168.

8618181993 is a `hidden beast` number, since 8 + 618 + 1 + 8 + 19 + 9 + 3 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1088802009 + 7529379984 = 32997^2 + 86772^2 .

It is not a de Polignac number, because 8618181993 - 2²² = 8613987689 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (8618181973) 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, 5380 + ... + 131397.

It is an arithmetic number, because the mean of its divisors is an integer number (1037529519).

Almost surely, 2^8618181993 is an apocalyptic number.

It is an amenable number.

8618181993 is a deficient number, since it is larger than the sum of its proper divisors (3832172235).

8618181993 is a wasteful number, since it uses less digits than its factorization.

8618181993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143784 (or 143781 counting only the distinct ones).

The product of its digits is 746496, while the sum is 54.

The square root of 8618181993 is about 92834.1639322507. The cubic root of 8618181993 is about 2050.2424454880.

The spelling of 8618181993 in words is "eight billion, six hundred eighteen million, one hundred eighty-one thousand, nine hundred ninety-three".