21131242443 has 16 divisors (see below), whose sum is σ = 31746470400. Its totient is φ = 13889078280.

The previous prime is 21131242427. The next prime is 21131242463. The reversal of 21131242443 is 34424213112.

21131242443 is a `hidden beast` number, since 211 + 3 + 1 + 2 + 4 + 2 + 443 = 666.

It is not a de Polignac number, because 21131242443 - 2⁴ = 21131242427 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21131242423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5509623 + ... + 5513456.

It is an arithmetic number, because the mean of its divisors is an integer number (1984154400).

Almost surely, 2^21131242443 is an apocalyptic number.

21131242443 is a deficient number, since it is larger than the sum of its proper divisors (10615227957).

21131242443 is a wasteful number, since it uses less digits than its factorization.

21131242443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11023159 (or 11023153 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

Adding to 21131242443 its reverse (34424213112), we get a palindrome (55555455555).

The spelling of 21131242443 in words is "twenty-one billion, one hundred thirty-one million, two hundred forty-two thousand, four hundred forty-three".