3121309 has 4 divisors (see below), whose sum is σ = 3172540. Its totient is φ = 3070080.

The previous prime is 3121303. The next prime is 3121333. The reversal of 3121309 is 9031213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9031213 = 19 ⋅475327.

It can be written as a sum of positive squares in 2 ways, for example, as 156025 + 2965284 = 395^2 + 1722^2 .

It is a cyclic number.

It is not a de Polignac number, because 3121309 - 2¹⁷ = 2990237 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 (3121303) 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, 25524 + ... + 25645.

It is an arithmetic number, because the mean of its divisors is an integer number (793135).

Almost surely, 2^3121309 is an apocalyptic number.

It is an amenable number.

3121309 is a deficient number, since it is larger than the sum of its proper divisors (51231).

3121309 is an equidigital number, since it uses as much as digits as its factorization.

3121309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51230.

The product of its (nonzero) digits is 162, while the sum is 19.

The square root of 3121309 is about 1766.7226720683. The cubic root of 3121309 is about 146.1433039701.

The spelling of 3121309 in words is "three million, one hundred twenty-one thousand, three hundred nine".