21221111100001 has 4 divisors (see below), whose sum is σ = 21221895380400. Its totient is φ = 21220326819604.

The previous prime is 21221111099983. The next prime is 21221111100041. The reversal of 21221111100001 is 10000111112212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21221111100001 - 2¹³ = 21221111091809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221111100041) 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 3 ways as a sum of consecutive naturals, for example, 392099611 + ... + 392153728.

It is an arithmetic number, because the mean of its divisors is an integer number (5305473845100).

Almost surely, 2^{21221111100001} is an apocalyptic number.

It is an amenable number.

21221111100001 is a deficient number, since it is larger than the sum of its proper divisors (784280399).

21221111100001 is an equidigital number, since it uses as much as digits as its factorization.

21221111100001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784280398.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21221111100001 its reverse (10000111112212), we get a palindrome (31221222212213).

The spelling of 21221111100001 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred thousand, one".