121231212221 has 4 divisors (see below), whose sum is σ = 138549956832. Its totient is φ = 103912467612.

The previous prime is 121231212211. The next prime is 121231212227. The reversal of 121231212221 is 122212132121.

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 121231212221 - 2¹⁴ = 121231195837 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 121231212193 and 121231212202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121231212227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8659372295 + ... + 8659372308.

It is an arithmetic number, because the mean of its divisors is an integer number (34637489208).

Almost surely, 2^121231212221 is an apocalyptic number.

It is an amenable number.

121231212221 is a deficient number, since it is larger than the sum of its proper divisors (17318744611).

121231212221 is an equidigital number, since it uses as much as digits as its factorization.

121231212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17318744610.

The product of its digits is 192, while the sum is 20.

Adding to 121231212221 its reverse (122212132121), we get a palindrome (243443344342).

The spelling of 121231212221 in words is "one hundred twenty-one billion, two hundred thirty-one million, two hundred twelve thousand, two hundred twenty-one".