1123721890561 has 4 divisors (see below), whose sum is σ = 1162470921300. Its totient is φ = 1084972859824.

The previous prime is 1123721890531. The next prime is 1123721890607. The reversal of 1123721890561 is 1650981273211.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 659798798400 + 463923092161 = 812280^2 + 681119^2 .

It is a cyclic number.

It is not a de Polignac number, because 1123721890561 - 2¹⁵ = 1123721857793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1123721890531) 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, 19374515326 + ... + 19374515383.

It is an arithmetic number, because the mean of its divisors is an integer number (290617730325).

Almost surely, 2^{1123721890561} is an apocalyptic number.

It is an amenable number.

1123721890561 is a deficient number, since it is larger than the sum of its proper divisors (38749030739).

1123721890561 is an equidigital number, since it uses as much as digits as its factorization.

1123721890561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38749030738.

The product of its (nonzero) digits is 181440, while the sum is 46.

The spelling of 1123721890561 in words is "one trillion, one hundred twenty-three billion, seven hundred twenty-one million, eight hundred ninety thousand, five hundred sixty-one".