2172981729 has 16 divisors (see below), whose sum is σ = 2945813312. Its totient is φ = 1424521728.

The previous prime is 2172981709. The next prime is 2172981743. The reversal of 2172981729 is 9271892712.

It is a happy number.

It is not a de Polignac number, because 2172981729 - 2¹⁷ = 2172850657 is a prime.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2172981709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 59082 + ... + 88524.

It is an arithmetic number, because the mean of its divisors is an integer number (184113332).

Almost surely, 2^2172981729 is an apocalyptic number.

It is an amenable number.

2172981729 is a deficient number, since it is larger than the sum of its proper divisors (772831583).

2172981729 is a wasteful number, since it uses less digits than its factorization.

2172981729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29856.

The product of its digits is 254016, while the sum is 48.

The square root of 2172981729 is about 46615.2521070089. The cubic root of 2172981729 is about 1295.2452995071.

The spelling of 2172981729 in words is "two billion, one hundred seventy-two million, nine hundred eighty-one thousand, seven hundred twenty-nine".