312078721 has 4 divisors (see below), whose sum is σ = 312540372. Its totient is φ = 311617072.

The previous prime is 312078719. The next prime is 312078727. The reversal of 312078721 is 127870213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127870213 = 61 ⋅2096233.

It can be written as a sum of positive squares in 2 ways, for example, as 272250000 + 39828721 = 16500^2 + 6311^2 .

It is a cyclic number.

It is not a de Polignac number, because 312078721 - 2¹ = 312078719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (312078727) 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, 229810 + ... + 231163.

It is an arithmetic number, because the mean of its divisors is an integer number (78135093).

Almost surely, 2^312078721 is an apocalyptic number.

It is an amenable number.

312078721 is a deficient number, since it is larger than the sum of its proper divisors (461651).

312078721 is an equidigital number, since it uses as much as digits as its factorization.

312078721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 461650.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 312078721 is about 17665.7499416243. The cubic root of 312078721 is about 678.2993264462.

The spelling of 312078721 in words is "three hundred twelve million, seventy-eight thousand, seven hundred twenty-one".