221312123121 has 8 divisors (see below), whose sum is σ = 303058042624. Its totient is φ = 143553809520.

The previous prime is 221312123113. The next prime is 221312123203. The reversal of 221312123121 is 121321213122.

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

It is not a de Polignac number, because 221312123121 - 2³ = 221312123113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221312123821) 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, 996901345 + ... + 996901566.

It is an arithmetic number, because the mean of its divisors is an integer number (37882255328).

Almost surely, 2^221312123121 is an apocalyptic number.

It is an amenable number.

221312123121 is a deficient number, since it is larger than the sum of its proper divisors (81745919503).

221312123121 is a wasteful number, since it uses less digits than its factorization.

221312123121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1993802951.

The product of its digits is 288, while the sum is 21.

Adding to 221312123121 its reverse (121321213122), we get a palindrome (342633336243).

Subtracting from 221312123121 its reverse (121321213122), we obtain a palindrome (99990909999).

The spelling of 221312123121 in words is "two hundred twenty-one billion, three hundred twelve million, one hundred twenty-three thousand, one hundred twenty-one".