121111121212221 has 16 divisors (see below), whose sum is σ = 186773777293824. Its totient is φ = 68372543471664.

The previous prime is 121111121212219. The next prime is 121111121212283. The reversal of 121111121212221 is 122212121111121.

It is not a de Polignac number, because 121111121212221 - 2¹ = 121111121212219 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121111121212321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34742144331 + ... + 34742147816.

It is an arithmetic number, because the mean of its divisors is an integer number (11673361080864).

Almost surely, 2^{121111121212221} is an apocalyptic number.

It is an amenable number.

121111121212221 is a deficient number, since it is larger than the sum of its proper divisors (65662656081603).

121111121212221 is an equidigital number, since it uses as much as digits as its factorization.

121111121212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69484292240.

The product of its digits is 64, while the sum is 21.

Adding to 121111121212221 its reverse (122212121111121), we get a palindrome (243323242323342).

The spelling of 121111121212221 in words is "one hundred twenty-one trillion, one hundred eleven billion, one hundred twenty-one million, two hundred twelve thousand, two hundred twenty-one".