121212121021 has 4 divisors (see below), whose sum is σ = 121471676352. Its totient is φ = 120952565692.

The previous prime is 121212121007. The next prime is 121212121153. The reversal of 121212121021 is 120121212121.

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 121212121021 - 2¹⁷ = 121211989949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 121212120986 and 121212121004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121212122021) 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, 129776965 + ... + 129777898.

It is an arithmetic number, because the mean of its divisors is an integer number (30367919088).

Almost surely, 2^121212121021 is an apocalyptic number.

It is an amenable number.

121212121021 is a deficient number, since it is larger than the sum of its proper divisors (259555331).

121212121021 is an equidigital number, since it uses as much as digits as its factorization.

121212121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259555330.

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

Adding to 121212121021 its reverse (120121212121), we get a palindrome (241333333142).

The spelling of 121212121021 in words is "one hundred twenty-one billion, two hundred twelve million, one hundred twenty-one thousand, twenty-one".