21221201212111 has 8 divisors (see below), whose sum is σ = 21236598087200. Its totient is φ = 21205805349888.

The previous prime is 21221201212109. The next prime is 21221201212117. The reversal of 21221201212111 is 11121210212212.

It is a happy number.

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 21221201212111 - 2¹ = 21221201212109 is a prime.

It is a super-2 number, since 2×21221201212111² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221201212117) 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, 44528815 + ... + 45002863.

It is an arithmetic number, because the mean of its divisors is an integer number (2654574760900).

Almost surely, 2^{21221201212111} is an apocalyptic number.

21221201212111 is a deficient number, since it is larger than the sum of its proper divisors (15396875089).

21221201212111 is a wasteful number, since it uses less digits than its factorization.

21221201212111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506433.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21221201212111 its reverse (11121210212212), we get a palindrome (32342411424323).

The spelling of 21221201212111 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred twelve thousand, one hundred eleven".