2121210121 has 6 divisors (see below), whose sum is σ = 2217447050. Its totient is φ = 2028983088.

The previous prime is 2121210107. The next prime is 2121210127. The reversal of 2121210121 is 1210121212.

2121210121 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in only one way, i.e., 1586906896 + 534303225 = 39836^2 + 23115^2 .

It is not a de Polignac number, because 2121210121 - 2²⁹ = 1584339209 is a prime.

It is a super-3 number, since 3×2121210121³ (a number of 29 digits) contains 333 as substring.

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 (2121210127) 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 5 ways as a sum of consecutive naturals, for example, 2004396 + ... + 2005453.

Almost surely, 2^2121210121 is an apocalyptic number.

It is an amenable number.

2121210121 is a deficient number, since it is larger than the sum of its proper divisors (96236929).

2121210121 is an equidigital number, since it uses as much as digits as its factorization.

2121210121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4009895 (or 4009872 counting only the distinct ones).

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

The square root of 2121210121 is about 46056.5969324699. The cubic root of 2121210121 is about 1284.8760388529.

Adding to 2121210121 its reverse (1210121212), we get a palindrome (3331331333).

It can be divided in two parts, 212 and 1210121, that multiplied together give a palindrome (256545652).

The spelling of 2121210121 in words is "two billion, one hundred twenty-one million, two hundred ten thousand, one hundred twenty-one".