312155521 has 4 divisors (see below), whose sum is σ = 312193492. Its totient is φ = 312117552.

The previous prime is 312155453. The next prime is 312155527. The reversal of 312155521 is 125551213.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 125551213 = 997 ⋅125929.

It can be written as a sum of positive squares in 2 ways, for example, as 25361296 + 286794225 = 5036^2 + 16935^2 .

It is a cyclic number.

It is not a de Polignac number, because 312155521 - 2¹⁵ = 312122753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (312155527) 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, 930 + ... + 25003.

It is an arithmetic number, because the mean of its divisors is an integer number (78048373).

Almost surely, 2^312155521 is an apocalyptic number.

It is an amenable number.

312155521 is a deficient number, since it is larger than the sum of its proper divisors (37971).

312155521 is a wasteful number, since it uses less digits than its factorization.

312155521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37970.

The product of its digits is 1500, while the sum is 25.

The square root of 312155521 is about 17667.9235056076. The cubic root of 312155521 is about 678.3549631730.

The spelling of 312155521 in words is "three hundred twelve million, one hundred fifty-five thousand, five hundred twenty-one".