311320152521221 has 4 divisors (see below), whose sum is σ = 311320191623500. Its totient is φ = 311320113418944.

The previous prime is 311320152521123. The next prime is 311320152521227. The reversal of 311320152521221 is 122125251023113.

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.

It can be written as a sum of positive squares in 2 ways, for example, as 268736514444225 + 42583638076996 = 16393185^2 + 6525614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-311320152521221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311320152521227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2857146 + ... + 25115803.

It is an arithmetic number, because the mean of its divisors is an integer number (77830047905875).

Almost surely, 2^{311320152521221} is an apocalyptic number.

It is an amenable number.

311320152521221 is a deficient number, since it is larger than the sum of its proper divisors (39102279).

311320152521221 is a wasteful number, since it uses less digits than its factorization.

311320152521221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39102278.

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 311320152521221 in words is "three hundred eleven trillion, three hundred twenty billion, one hundred fifty-two million, five hundred twenty-one thousand, two hundred twenty-one".