21221310001 has 16 divisors (see below), whose sum is σ = 22678373520. Its totient is φ = 19788021760.

The previous prime is 21221309987. The next prime is 21221310013. The reversal of 21221310001 is 10001312212.

It can be written as a sum of positive squares in 8 ways, for example, as 1795640625 + 19425669376 = 42375^2 + 139376^2 .

It is not a de Polignac number, because 21221310001 - 2¹³ = 21221301809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221310031) 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 15 ways as a sum of consecutive naturals, for example, 1204665 + ... + 1222153.

It is an arithmetic number, because the mean of its divisors is an integer number (1417398345).

Almost surely, 2^21221310001 is an apocalyptic number.

It is an amenable number.

21221310001 is a deficient number, since it is larger than the sum of its proper divisors (1457063519).

21221310001 is a wasteful number, since it uses less digits than its factorization.

21221310001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18164.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21221310001 its reverse (10001312212), we get a palindrome (31222622213).

The spelling of 21221310001 in words is "twenty-one billion, two hundred twenty-one million, three hundred ten thousand, one".