313781 has 4 divisors (see below), whose sum is σ = 337932. Its totient is φ = 289632.

The previous prime is 313777. The next prime is 313783. The reversal of 313781 is 187313.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 187313 = 7 ⋅26759.

It can be written as a sum of positive squares in 2 ways, for example, as 128881 + 184900 = 359^2 + 430^2 .

It is a cyclic number.

It is not a de Polignac number, because 313781 - 2² = 313777 is a prime.

It is a super-2 number, since 2×313781² = 196917031922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 313781.

It is not an unprimeable number, because it can be changed into a prime (313783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12056 + ... + 12081.

It is an arithmetic number, because the mean of its divisors is an integer number (84483).

2³¹³⁷⁸¹ is an apocalyptic number.

It is an amenable number.

313781 is a deficient number, since it is larger than the sum of its proper divisors (24151).

313781 is a wasteful number, since it uses less digits than its factorization.

313781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24150.

The product of its digits is 504, while the sum is 23.

The square root of 313781 is about 560.1615838310. The cubic root of 313781 is about 67.9530385096.

The spelling of 313781 in words is "three hundred thirteen thousand, seven hundred eighty-one".