312749 has 4 divisors (see below), whose sum is σ = 331164. Its totient is φ = 294336.

The previous prime is 312743. The next prime is 312757. The reversal of 312749 is 947213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 947213 = 661 ⋅1433.

It can be written as a sum of positive squares in 2 ways, for example, as 265225 + 47524 = 515^2 + 218^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-312749 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 (312743) 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, 9182 + ... + 9215.

It is an arithmetic number, because the mean of its divisors is an integer number (82791).

2³¹²⁷⁴⁹ is an apocalyptic number.

It is an amenable number.

312749 is a deficient number, since it is larger than the sum of its proper divisors (18415).

312749 is a wasteful number, since it uses less digits than its factorization.

312749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18414.

The product of its digits is 1512, while the sum is 26.

The square root of 312749 is about 559.2396623989. The cubic root of 312749 is about 67.8784593629.

The spelling of 312749 in words is "three hundred twelve thousand, seven hundred forty-nine".