121220212121 has 8 divisors (see below), whose sum is σ = 128451345480. Its totient is φ = 114000249088.

The previous prime is 121220212117. The next prime is 121220212159. The reversal of 121220212121 is 121212022121.

It can be written as a sum of positive squares in 4 ways, for example, as 86786214025 + 34433998096 = 294595^2 + 185564^2 .

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 121220212121 - 2² = 121220212117 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121220212121.

It is not an unprimeable number, because it can be changed into a prime (121220212721) 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, 2770226 + ... + 2813643.

It is an arithmetic number, because the mean of its divisors is an integer number (16056418185).

Almost surely, 2^121220212121 is an apocalyptic number.

It is an amenable number.

121220212121 is a deficient number, since it is larger than the sum of its proper divisors (7231133359).

121220212121 is a wasteful number, since it uses less digits than its factorization.

121220212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5585163.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 121220212121 its reverse (121212022121), we get a palindrome (242432234242).

The spelling of 121220212121 in words is "one hundred twenty-one billion, two hundred twenty million, two hundred twelve thousand, one hundred twenty-one".