312121213 has 4 divisors (see below), whose sum is σ = 312441660. Its totient is φ = 311800768.

The previous prime is 312121129. The next prime is 312121217.

312121213 is nontrivially palindromic in base 10.

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 297666009 + 14455204 = 17253^2 + 3802^2 .

It is a cyclic number.

It is not a de Polignac number, because 312121213 - 2⁹ = 312120701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (312121217) 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, 158758 + ... + 160711.

It is an arithmetic number, because the mean of its divisors is an integer number (78110415).

Almost surely, 2^312121213 is an apocalyptic number.

It is an amenable number.

312121213 is a deficient number, since it is larger than the sum of its proper divisors (320447).

312121213 is an equidigital number, since it uses as much as digits as its factorization.

312121213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320446.

The product of its digits is 72, while the sum is 16.

The square root of 312121213 is about 17666.9525668690. The cubic root of 312121213 is about 678.3301103318.

The spelling of 312121213 in words is "three hundred twelve million, one hundred twenty-one thousand, two hundred thirteen".