318212921 has 4 divisors (see below), whose sum is σ = 342690852. Its totient is φ = 293734992.

The previous prime is 318212897. The next prime is 318212927. The reversal of 318212921 is 129212813.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129212813 = 211 ⋅612383.

It can be written as a sum of positive squares in 2 ways, for example, as 88266025 + 229946896 = 9395^2 + 15164^2 .

It is a cyclic number.

It is not a de Polignac number, because 318212921 - 2¹⁰ = 318211897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (318212927) 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, 12238946 + ... + 12238971.

It is an arithmetic number, because the mean of its divisors is an integer number (85672713).

Almost surely, 2^318212921 is an apocalyptic number.

It is an amenable number.

318212921 is a deficient number, since it is larger than the sum of its proper divisors (24477931).

318212921 is a wasteful number, since it uses less digits than its factorization.

318212921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24477930.

The product of its digits is 1728, while the sum is 29.

The square root of 318212921 is about 17838.5235095285. The cubic root of 318212921 is about 682.7147251575.

The spelling of 318212921 in words is "three hundred eighteen million, two hundred twelve thousand, nine hundred twenty-one".