311686607521 has 3 divisors (see below), whose sum is σ = 311687165811. Its totient is φ = 311686049232.

The previous prime is 311686607497. The next prime is 311686607587. The reversal of 311686607521 is 125706686113.

It is a happy number.

The square root of 311686607521 is 558289.

It is a perfect power (a square), and thus also a powerful number.

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: 125706686113 = 4493 ⋅27978341.

It can be written as a sum of positive squares in only one way, i.e., 44314881121 + 267371726400 = 210511^2 + 517080^2 .

It is not a de Polignac number, because 311686607521 - 2¹¹ = 311686605473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (311686407521) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 279145 + ... + 837433.

It is an arithmetic number, because the mean of its divisors is an integer number (103895721937).

Almost surely, 2^311686607521 is an apocalyptic number.

311686607521 is the 558289-th square number.

311686607521 is the 279145-th centered octagonal number.

It is an amenable number.

311686607521 is a deficient number, since it is larger than the sum of its proper divisors (558290).

311686607521 is an frugal number, since it uses more digits than its factorization.

311686607521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1116578 (or 558289 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 46.

The spelling of 311686607521 in words is "three hundred eleven billion, six hundred eighty-six million, six hundred seven thousand, five hundred twenty-one".