21642444136 has 16 divisors (see below), whose sum is σ = 42343912800. Its totient is φ = 10350734064.

The previous prime is 21642444091. The next prime is 21642444149. The reversal of 21642444136 is 63144424612.

It is a junction number, because it is equal to n+sod(n) for n = 21642444095 and 21642444104.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58810806 + ... + 58811173.

It is an arithmetic number, because the mean of its divisors is an integer number (2646494550).

Almost surely, 2^21642444136 is an apocalyptic number.

It is an amenable number.

21642444136 is a deficient number, since it is larger than the sum of its proper divisors (20701468664).

21642444136 is a wasteful number, since it uses less digits than its factorization.

21642444136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117622008 (or 117622004 counting only the distinct ones).

The product of its digits is 110592, while the sum is 37.

Adding to 21642444136 its reverse (63144424612), we get a palindrome (84786868748).

The spelling of 21642444136 in words is "twenty-one billion, six hundred forty-two million, four hundred forty-four thousand, one hundred thirty-six".