2172221121 has 16 divisors (see below), whose sum is σ = 3504760704. Its totient is φ = 1168253184.

The previous prime is 2172221099. The next prime is 2172221143. The reversal of 2172221121 is 1211222712.

It is an interprime number because it is at equal distance from previous prime (2172221099) and next prime (2172221143).

It is not a de Polignac number, because 2172221121 - 2¹⁰ = 2172220097 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2172221521) 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, 3041970 + ... + 3042683.

It is an arithmetic number, because the mean of its divisors is an integer number (219047544).

Almost surely, 2^2172221121 is an apocalyptic number.

2172221121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2172221121 is a deficient number, since it is larger than the sum of its proper divisors (1332539583).

2172221121 is a wasteful number, since it uses less digits than its factorization.

2172221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6084680.

The product of its digits is 224, while the sum is 21.

The square root of 2172221121 is about 46607.0930331425. The cubic root of 2172221121 is about 1295.0941571248.

Adding to 2172221121 its reverse (1211222712), we get a palindrome (3383443833).

The spelling of 2172221121 in words is "two billion, one hundred seventy-two million, two hundred twenty-one thousand, one hundred twenty-one".