1822872721 has 4 divisors (see below), whose sum is σ = 1839004452. Its totient is φ = 1806740992.

The previous prime is 1822872713. The next prime is 1822872731. The reversal of 1822872721 is 1272782281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1272782281 = 71 ⋅17926511.

It can be written as a sum of positive squares in 2 ways, for example, as 921972496 + 900900225 = 30364^2 + 30015^2 .

It is a cyclic number.

It is not a de Polignac number, because 1822872721 - 2³ = 1822872713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1822872731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8065696 + ... + 8065921.

It is an arithmetic number, because the mean of its divisors is an integer number (459751113).

Almost surely, 2^1822872721 is an apocalyptic number.

It is an amenable number.

1822872721 is a deficient number, since it is larger than the sum of its proper divisors (16131731).

1822872721 is a wasteful number, since it uses less digits than its factorization.

1822872721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16131730.

The product of its digits is 50176, while the sum is 40.

The square root of 1822872721 is about 42695.1135494450. The cubic root of 1822872721 is about 1221.5711909646.

The spelling of 1822872721 in words is "one billion, eight hundred twenty-two million, eight hundred seventy-two thousand, seven hundred twenty-one".