21444210121 has 8 divisors (see below), whose sum is σ = 21568380680. Its totient is φ = 21320174592.

The previous prime is 21444210059. The next prime is 21444210133. The reversal of 21444210121 is 12101244412.

It can be written as a sum of positive squares in 4 ways, for example, as 690638400 + 20753571721 = 26280^2 + 144061^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21444210121 - 2¹³ = 21444201929 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21444210092 and 21444210101.

It is not an unprimeable number, because it can be changed into a prime (21444210721) 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, 293935 + ... + 359563.

It is an arithmetic number, because the mean of its divisors is an integer number (2696047585).

Almost surely, 2^21444210121 is an apocalyptic number.

It is an amenable number.

21444210121 is a deficient number, since it is larger than the sum of its proper divisors (124170559).

21444210121 is a wasteful number, since it uses less digits than its factorization.

21444210121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67515.

The product of its (nonzero) digits is 512, while the sum is 22.

Adding to 21444210121 its reverse (12101244412), we get a palindrome (33545454533).

The spelling of 21444210121 in words is "twenty-one billion, four hundred forty-four million, two hundred ten thousand, one hundred twenty-one".