1221001112221 has 4 divisors (see below), whose sum is σ = 1332001213344. Its totient is φ = 1110001011100.

The previous prime is 1221001112167. The next prime is 1221001112267. The reversal of 1221001112221 is 1222111001221.

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 1221001112221 - 2⁹ = 1221001111709 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221001112195 and 1221001112204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221001112281) 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, 55500050545 + ... + 55500050566.

It is an arithmetic number, because the mean of its divisors is an integer number (333000303336).

Almost surely, 2^{1221001112221} is an apocalyptic number.

1221001112221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221001112221 is a deficient number, since it is larger than the sum of its proper divisors (111000101123).

1221001112221 is a wasteful number, since it uses less digits than its factorization.

1221001112221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111000101122.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221001112221 its reverse (1222111001221), we get a palindrome (2443112113442).

It can be divided in two parts, 122100 and 1112221, that added together give a palindrome (1234321).

The spelling of 1221001112221 in words is "one trillion, two hundred twenty-one billion, one million, one hundred twelve thousand, two hundred twenty-one".