2172821618 has 16 divisors (see below), whose sum is σ = 3556271520. Its totient is φ = 987439200.

The previous prime is 2172821617. The next prime is 2172821639. The reversal of 2172821618 is 8161282712.

It is not an unprimeable number, because it can be changed into a prime (2172821617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 157478 + ... + 170718.

It is an arithmetic number, because the mean of its divisors is an integer number (222266970).

Almost surely, 2^2172821618 is an apocalyptic number.

2172821618 is a deficient number, since it is larger than the sum of its proper divisors (1383449902).

2172821618 is a wasteful number, since it uses less digits than its factorization.

2172821618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20713.

The product of its digits is 21504, while the sum is 38.

The square root of 2172821618 is about 46613.5347082797. The cubic root of 2172821618 is about 1295.2134863674.

The spelling of 2172821618 in words is "two billion, one hundred seventy-two million, eight hundred twenty-one thousand, six hundred eighteen".