1129122721 has 4 divisors (see below), whose sum is σ = 1129652244. Its totient is φ = 1128593200.

The previous prime is 1129122719. The next prime is 1129122737. The reversal of 1129122721 is 1272219211.

1129122721 = 23760² + 23761².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1272219211 = 37 ⋅34384303.

It can be written as a sum of positive squares in 2 ways, for example, as 564585121 + 564537600 = 23761^2 + 23760^2 .

It is a cyclic number.

It is not a de Polignac number, because 1129122721 - 2¹ = 1129122719 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1129122721.

It is not an unprimeable number, because it can be changed into a prime (1129122791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 261550 + ... + 265831.

It is an arithmetic number, because the mean of its divisors is an integer number (282413061).

Almost surely, 2^1129122721 is an apocalyptic number.

1129122721 is the 23761-st centered square number.

It is an amenable number.

1129122721 is a deficient number, since it is larger than the sum of its proper divisors (529523).

1129122721 is an equidigital number, since it uses as much as digits as its factorization.

1129122721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 529522.

The product of its digits is 1008, while the sum is 28.

The square root of 1129122721 is about 33602.4213562059. The cubic root of 1129122721 is about 1041.3108227896.

The spelling of 1129122721 in words is "one billion, one hundred twenty-nine million, one hundred twenty-two thousand, seven hundred twenty-one".