21202144424 has 16 divisors (see below), whose sum is σ = 39924642420. Its totient is φ = 10555573120.

The previous prime is 21202144421. The next prime is 21202144459. The reversal of 21202144424 is 42444120212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17659752100 + 3542392324 = 132890^2 + 59518^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21202144393 and 21202144402.

It is not an unprimeable number, because it can be changed into a prime (21202144421) 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, 5685407 + ... + 5689134.

Almost surely, 2^21202144424 is an apocalyptic number.

It is an amenable number.

21202144424 is a deficient number, since it is larger than the sum of its proper divisors (18722497996).

21202144424 is a wasteful number, since it uses less digits than its factorization.

21202144424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11374780 (or 11374776 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 26.

Adding to 21202144424 its reverse (42444120212), we get a palindrome (63646264636).

The spelling of 21202144424 in words is "twenty-one billion, two hundred two million, one hundred forty-four thousand, four hundred twenty-four".