21447123436 has 6 divisors (see below), whose sum is σ = 37532466020. Its totient is φ = 10723561716.

The previous prime is 21447123427. The next prime is 21447123437. The reversal of 21447123436 is 63432174412.

It is a junction number, because it is equal to n+sod(n) for n = 21447123395 and 21447123404.

It is not an unprimeable number, because it can be changed into a prime (21447123437) 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 as a sum of consecutive naturals, namely, 2680890426 + ... + 2680890433.

Almost surely, 2^21447123436 is an apocalyptic number.

It is an amenable number.

21447123436 is a deficient number, since it is larger than the sum of its proper divisors (16085342584).

21447123436 is a wasteful number, since it uses less digits than its factorization.

21447123436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5361780863 (or 5361780861 counting only the distinct ones).

The product of its digits is 96768, while the sum is 37.

Adding to 21447123436 its reverse (63432174412), we get a palindrome (84879297848).

The spelling of 21447123436 in words is "twenty-one billion, four hundred forty-seven million, one hundred twenty-three thousand, four hundred thirty-six".