16331231561 has 8 divisors (see below), whose sum is σ = 16732306248. Its totient is φ = 15930288000.

The previous prime is 16331231503. The next prime is 16331231563. The reversal of 16331231561 is 16513213361.

It can be written as a sum of positive squares in 4 ways, for example, as 44622400 + 16286609161 = 6680^2 + 127619^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16331231561 - 2¹⁴ = 16331215177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16331231563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 248651 + ... + 307391.

It is an arithmetic number, because the mean of its divisors is an integer number (2091538281).

Almost surely, 2^16331231561 is an apocalyptic number.

It is an amenable number.

16331231561 is a deficient number, since it is larger than the sum of its proper divisors (401074687).

16331231561 is an equidigital number, since it uses as much as digits as its factorization.

16331231561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65563.

The product of its digits is 9720, while the sum is 32.

The spelling of 16331231561 in words is "sixteen billion, three hundred thirty-one million, two hundred thirty-one thousand, five hundred sixty-one".