21121101221 has 8 divisors (see below), whose sum is σ = 23418926688. Its totient is φ = 18886230000.

The previous prime is 21121101173. The next prime is 21121101247. The reversal of 21121101221 is 12210112112.

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

It is not a de Polignac number, because 21121101221 - 2¹⁴ = 21121084837 is a prime.

It is a super-2 number, since 2×21121101221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121101196 and 21121101205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121161221) 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, 15737855 + ... + 15739196.

It is an arithmetic number, because the mean of its divisors is an integer number (2927365836).

Almost surely, 2^21121101221 is an apocalyptic number.

It is an amenable number.

21121101221 is a deficient number, since it is larger than the sum of its proper divisors (2297825467).

21121101221 is a wasteful number, since it uses less digits than its factorization.

21121101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31477123.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21121101221 its reverse (12210112112), we get a palindrome (33331213333).

The spelling of 21121101221 in words is "twenty-one billion, one hundred twenty-one million, one hundred one thousand, two hundred twenty-one".