89721021618 has 54 divisors (see below), whose sum is σ = 206552963799. Its totient is φ = 28140993792.

The previous prime is 89721021571. The next prime is 89721021619. The reversal of 89721021618 is 81612012798.

89721021618 is a `hidden beast` number, since 8 + 9 + 7 + 2 + 1 + 0 + 21 + 618 = 666.

It can be written as a sum of positive squares in 5 ways, for example, as 13943594889 + 75777426729 = 118083^2 + 275277^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=211803.

It is not an unprimeable number, because it can be changed into a prime (89721021619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 21601830 + ... + 21605982.

Almost surely, 2^89721021618 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 89721021618

89721021618 is an abundant number, since it is smaller than the sum of its proper divisors (116831942181).

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

89721021618 is an equidigital number, since it uses as much as digits as its factorization.

89721021618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8348 (or 4175 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 45.

The spelling of 89721021618 in words is "eighty-nine billion, seven hundred twenty-one million, twenty-one thousand, six hundred eighteen".