21044220623 has 4 divisors (see below), whose sum is σ = 21049321440. Its totient is φ = 21039119808.

The previous prime is 21044220577. The next prime is 21044220667. The reversal of 21044220623 is 32602244012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21044220623 - 2¹⁸ = 21043958479 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21044220592 and 21044220601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21044220023) 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 in 3 ways as a sum of consecutive naturals, for example, 2544215 + ... + 2552472.

It is an arithmetic number, because the mean of its divisors is an integer number (5262330360).

Almost surely, 2^21044220623 is an apocalyptic number.

21044220623 is a deficient number, since it is larger than the sum of its proper divisors (5100817).

21044220623 is an equidigital number, since it uses as much as digits as its factorization.

21044220623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5100816.

The product of its (nonzero) digits is 4608, while the sum is 26.

Adding to 21044220623 its reverse (32602244012), we get a palindrome (53646464635).

The spelling of 21044220623 in words is "twenty-one billion, forty-four million, two hundred twenty thousand, six hundred twenty-three".