21644144743 has 4 divisors (see below), whose sum is σ = 23309078968. Its totient is φ = 19979210520.

The previous prime is 21644144737. The next prime is 21644144773. The reversal of 21644144743 is 34744144612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21644144743 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21644144696 and 21644144705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21644144773) 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, 832467093 + ... + 832467118.

It is an arithmetic number, because the mean of its divisors is an integer number (5827269742).

Almost surely, 2^21644144743 is an apocalyptic number.

21644144743 is a deficient number, since it is larger than the sum of its proper divisors (1664934225).

21644144743 is a wasteful number, since it uses less digits than its factorization.

21644144743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1664934224.

The product of its digits is 258048, while the sum is 40.

The spelling of 21644144743 in words is "twenty-one billion, six hundred forty-four million, one hundred forty-four thousand, seven hundred forty-three".