121321220021 has 4 divisors (see below), whose sum is σ = 121343200044. Its totient is φ = 121299240000.

The previous prime is 121321220017. The next prime is 121321220029. The reversal of 121321220021 is 120022123121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 35377848100 + 85943371921 = 188090^2 + 293161^2 .

It is a cyclic number.

It is not a de Polignac number, because 121321220021 - 2² = 121321220017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121321220029) 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, 10981730 + ... + 10992771.

It is an arithmetic number, because the mean of its divisors is an integer number (30335800011).

Almost surely, 2^121321220021 is an apocalyptic number.

It is an amenable number.

121321220021 is a deficient number, since it is larger than the sum of its proper divisors (21980023).

121321220021 is an equidigital number, since it uses as much as digits as its factorization.

121321220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21980022.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 121321220021 its reverse (120022123121), we get a palindrome (241343343142).

The spelling of 121321220021 in words is "one hundred twenty-one billion, three hundred twenty-one million, two hundred twenty thousand, twenty-one".