21631446225161 has 4 divisors (see below), whose sum is σ = 21631469386500. Its totient is φ = 21631423063824.

The previous prime is 21631446225143. The next prime is 21631446225187. The reversal of 21631446225161 is 16152264413612.

It is a happy number.

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 14690624137225 + 6940822087936 = 3832835^2 + 2634544^2 .

It is a cyclic number.

It is not a de Polignac number, because 21631446225161 - 2³⁴ = 21614266355977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21631446225101) 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, 10118186 + ... + 12068163.

It is an arithmetic number, because the mean of its divisors is an integer number (5407867346625).

Almost surely, 2^{21631446225161} is an apocalyptic number.

It is an amenable number.

21631446225161 is a deficient number, since it is larger than the sum of its proper divisors (23161339).

21631446225161 is an equidigital number, since it uses as much as digits as its factorization.

21631446225161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23161338.

The product of its digits is 414720, while the sum is 44.

The spelling of 21631446225161 in words is "twenty-one trillion, six hundred thirty-one billion, four hundred forty-six million, two hundred twenty-five thousand, one hundred sixty-one".