312133721 has 4 divisors (see below), whose sum is σ = 318774912. Its totient is φ = 305492532.

The previous prime is 312133711. The next prime is 312133727. The reversal of 312133721 is 127331213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 312133721 - 2¹⁸ = 311871577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (312133727) 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 3 ways as a sum of consecutive naturals, for example, 3320525 + ... + 3320618.

It is an arithmetic number, because the mean of its divisors is an integer number (79693728).

Almost surely, 2^312133721 is an apocalyptic number.

It is an amenable number.

312133721 is a deficient number, since it is larger than the sum of its proper divisors (6641191).

312133721 is an equidigital number, since it uses as much as digits as its factorization.

312133721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6641190.

The product of its digits is 756, while the sum is 23.

The square root of 312133721 is about 17667.3065575939. The cubic root of 312133721 is about 678.3391713839.

Adding to 312133721 its reverse (127331213), we get a palindrome (439464934).

The spelling of 312133721 in words is "three hundred twelve million, one hundred thirty-three thousand, seven hundred twenty-one".