213242121 has 12 divisors (see below), whose sum is σ = 308180548. Its totient is φ = 142085664.

The previous prime is 213242083. The next prime is 213242129. The reversal of 213242121 is 121242312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 109935225 + 103306896 = 10485^2 + 10164^2 .

It is not a de Polignac number, because 213242121 - 2¹⁰ = 213241097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 213242094 and 213242103.

It is not an unprimeable number, because it can be changed into a prime (213242129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15471 + ... + 25803.

Almost surely, 2^213242121 is an apocalyptic number.

It is an amenable number.

213242121 is a deficient number, since it is larger than the sum of its proper divisors (94938427).

213242121 is a wasteful number, since it uses less digits than its factorization.

213242121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12632 (or 12629 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 213242121 is about 14602.8120921965. The cubic root of 213242121 is about 597.4354625298.

Adding to 213242121 its reverse (121242312), we get a palindrome (334484433).

It can be divided in two parts, 2132 and 42121, that added together give a triangular number (44253 = T₂₉₇).

The spelling of 213242121 in words is "two hundred thirteen million, two hundred forty-two thousand, one hundred twenty-one".