1221212121221 has 8 divisors (see below), whose sum is σ = 1233490896000. Its totient is φ = 1208937024400.

The previous prime is 1221212121139. The next prime is 1221212121253.

1221212121221 is nontrivially palindromic in base 10.

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

It is a cyclic number.

It is not a de Polignac number, because 1221212121221 - 2³⁴ = 1204032252037 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221212121193 and 1221212121202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221212121421) 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, 249641 + ... + 1582638.

It is an arithmetic number, because the mean of its divisors is an integer number (154186362000).

Almost surely, 2^{1221212121221} is an apocalyptic number.

It is an amenable number.

1221212121221 is a deficient number, since it is larger than the sum of its proper divisors (12278774779).

1221212121221 is a wasteful number, since it uses less digits than its factorization.

1221212121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1838979.

The product of its digits is 128, while the sum is 20.

The spelling of 1221212121221 in words is "one trillion, two hundred twenty-one billion, two hundred twelve million, one hundred twenty-one thousand, two hundred twenty-one".