8721385618 has 16 divisors (see below), whose sum is σ = 14302198656. Its totient is φ = 3955699440.

The previous prime is 8721385609. The next prime is 8721385637. The reversal of 8721385618 is 8165831278.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 417921 + ... + 438292.

It is an arithmetic number, because the mean of its divisors is an integer number (893887416).

Almost surely, 2^8721385618 is an apocalyptic number.

8721385618 is a deficient number, since it is larger than the sum of its proper divisors (5580813038).

8721385618 is a wasteful number, since it uses less digits than its factorization.

8721385618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 856689.

The product of its digits is 645120, while the sum is 49.

The square root of 8721385618 is about 93388.3591139709. The cubic root of 8721385618 is about 2058.3939486478.

The spelling of 8721385618 in words is "eight billion, seven hundred twenty-one million, three hundred eighty-five thousand, six hundred eighteen".