2121012121 has 4 divisors (see below), whose sum is σ = 2194150500. Its totient is φ = 2047873744.

The previous prime is 2121012097. The next prime is 2121012139. The reversal of 2121012121 is 1212101212.

2121012121 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

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 1020099721 + 1100912400 = 31939^2 + 33180^2 .

It is not a de Polignac number, because 2121012121 - 2⁹ = 2121011609 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121012721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36569146 + ... + 36569203.

It is an arithmetic number, because the mean of its divisors is an integer number (548537625).

Almost surely, 2^2121012121 is an apocalyptic number.

It is an amenable number.

2121012121 is a deficient number, since it is larger than the sum of its proper divisors (73138379).

2121012121 is an equidigital number, since it uses as much as digits as its factorization.

2121012121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73138378.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 2121012121 is about 46054.4473531059. The cubic root of 2121012121 is about 1284.8360595711.

Adding to 2121012121 its reverse (1212101212), we get a palindrome (3333113333).

The spelling of 2121012121 in words is "two billion, one hundred twenty-one million, twelve thousand, one hundred twenty-one".