312331221 has 20 divisors (see below), whose sum is σ = 467045964. Its totient is φ = 208008000.

The previous prime is 312331213. The next prime is 312331277. The reversal of 312331221 is 122133213.

312331221 is a `hidden beast` number, since 312 + 331 + 2 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 179828100 + 132503121 = 13410^2 + 11511^2 .

It is not a de Polignac number, because 312331221 - 2³ = 312331213 is a prime.

It is a super-2 number, since 2×312331221² = 195101583222701682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 312331194 and 312331203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (312331211) 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 19 ways as a sum of consecutive naturals, for example, 144811 + ... + 146951.

Almost surely, 2^312331221 is an apocalyptic number.

It is an amenable number.

312331221 is a deficient number, since it is larger than the sum of its proper divisors (154714743).

312331221 is a wasteful number, since it uses less digits than its factorization.

312331221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3954 (or 3945 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 312331221 is about 17672.8950939002. The cubic root of 312331221 is about 678.4822123635.

Adding to 312331221 its reverse (122133213), we get a palindrome (434464434).

The spelling of 312331221 in words is "three hundred twelve million, three hundred thirty-one thousand, two hundred twenty-one".