21221111221001 has 16 divisors (see below), whose sum is σ = 23620997568000. Its totient is φ = 18981158716800.

The previous prime is 21221111220949. The next prime is 21221111221019. The reversal of 21221111221001 is 10012211112212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221111221001 is a prime.

It is a super-2 number, since 2×21221111221001² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21221111221061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 439354526 + ... + 439402823.

It is an arithmetic number, because the mean of its divisors is an integer number (1476312348000).

Almost surely, 2^{21221111221001} is an apocalyptic number.

It is an amenable number.

21221111221001 is a deficient number, since it is larger than the sum of its proper divisors (2399886346999).

21221111221001 is a wasteful number, since it uses less digits than its factorization.

21221111221001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 878757440.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21221111221001 its reverse (10012211112212), we get a palindrome (31233322333213).

The spelling of 21221111221001 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, two hundred twenty-one thousand, one".