313172021 has 2 divisors, whose sum is σ = 313172022. Its totient is φ = 313172020.

The previous prime is 313172017. The next prime is 313172077. The reversal of 313172021 is 120271313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 279357796 + 33814225 = 16714^2 + 5815^2 .

It is an emirp because it is prime and its reverse (120271313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 313172021 - 2² = 313172017 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 313171984 and 313172002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (313102021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156586010 + 156586011.

It is an arithmetic number, because the mean of its divisors is an integer number (156586011).

Almost surely, 2^313172021 is an apocalyptic number.

It is an amenable number.

313172021 is a deficient number, since it is larger than the sum of its proper divisors (1).

313172021 is an equidigital number, since it uses as much as digits as its factorization.

313172021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 313172021 is about 17696.6669460664. Note that the first 3 decimals coincide. The cubic root of 313172021 is about 679.0904947121.

The spelling of 313172021 in words is "three hundred thirteen million, one hundred seventy-two thousand, twenty-one".