21444432131 has 4 divisors (see below), whose sum is σ = 21849044112. Its totient is φ = 21039820152.

The previous prime is 21444432127. The next prime is 21444432143. The reversal of 21444432131 is 13123444412.

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

It is a cyclic number.

It is not a de Polignac number, because 21444432131 - 2² = 21444432127 is a prime.

It is a super-2 number, since 2×21444432131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21444432094 and 21444432103.

It is not an unprimeable number, because it can be changed into a prime (21444432161) 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, 202305911 + ... + 202306016.

It is an arithmetic number, because the mean of its divisors is an integer number (5462261028).

Almost surely, 2^21444432131 is an apocalyptic number.

21444432131 is a deficient number, since it is larger than the sum of its proper divisors (404611981).

21444432131 is an equidigital number, since it uses as much as digits as its factorization.

21444432131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404611980.

The product of its digits is 9216, while the sum is 29.

Adding to 21444432131 its reverse (13123444412), we get a palindrome (34567876543).

The spelling of 21444432131 in words is "twenty-one billion, four hundred forty-four million, four hundred thirty-two thousand, one hundred thirty-one".