313240021 has 2 divisors, whose sum is σ = 313240022. Its totient is φ = 313240020.

The previous prime is 313240019. The next prime is 313240033. The reversal of 313240021 is 120042313.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 306635121 + 6604900 = 17511^2 + 2570^2 .

It is a cyclic number.

It is not a de Polignac number, because 313240021 - 2¹ = 313240019 is a prime.

Together with 313240019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 313239977 and 313240004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (313240051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156620010 + 156620011.

It is an arithmetic number, because the mean of its divisors is an integer number (156620011).

Almost surely, 2^313240021 is an apocalyptic number.

It is an amenable number.

313240021 is a deficient number, since it is larger than the sum of its proper divisors (1).

313240021 is an equidigital number, since it uses as much as digits as its factorization.

313240021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 313240021 is about 17698.5881075299. The cubic root of 313240021 is about 679.1396421547.

Adding to 313240021 its reverse (120042313), we get a palindrome (433282334).

The spelling of 313240021 in words is "three hundred thirteen million, two hundred forty thousand, twenty-one".