313721 has 2 divisors, whose sum is σ = 313722. Its totient is φ = 313720.

The previous prime is 313717. The next prime is 313727. The reversal of 313721 is 127313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 313600 + 121 = 560^2 + 11^2 .

It is a cyclic number.

It is not a de Polignac number, because 313721 - 2² = 313717 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 313721.

It is not a weakly prime, because it can be changed into another prime (313727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156860 + 156861.

It is an arithmetic number, because the mean of its divisors is an integer number (156861).

2³¹³⁷²¹ is an apocalyptic number.

It is an amenable number.

313721 is a deficient number, since it is larger than the sum of its proper divisors (1).

313721 is an equidigital number, since it uses as much as digits as its factorization.

313721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 126, while the sum is 17.

The square root of 313721 is about 560.1080252951. The cubic root of 313721 is about 67.9487069937.

The spelling of 313721 in words is "three hundred thirteen thousand, seven hundred twenty-one".