21444004021 has 8 divisors (see below), whose sum is σ = 23428857888. Its totient is φ = 19465050000.

The previous prime is 21444004013. The next prime is 21444004073. The reversal of 21444004021 is 12040044412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21444004021 - 2³ = 21444004013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21444003983 and 21444004001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444004091) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1467355 + ... + 1481896.

It is an arithmetic number, because the mean of its divisors is an integer number (2928607236).

Almost surely, 2^21444004021 is an apocalyptic number.

It is an amenable number.

21444004021 is a deficient number, since it is larger than the sum of its proper divisors (1984853867).

21444004021 is a wasteful number, since it uses less digits than its factorization.

21444004021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2949923.

The product of its (nonzero) digits is 1024, while the sum is 22.

Adding to 21444004021 its reverse (12040044412), we get a palindrome (33484048433).

The spelling of 21444004021 in words is "twenty-one billion, four hundred forty-four million, four thousand, twenty-one".