3121689 has 4 divisors (see below), whose sum is σ = 4162256. Its totient is φ = 2081124.

The previous prime is 3121667. The next prime is 3121691. The reversal of 3121689 is 9861213.

3121689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9861213 = 3 ⋅3287071.

It is not a de Polignac number, because 3121689 - 2⁷ = 3121561 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3121609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 520279 + ... + 520284.

It is an arithmetic number, because the mean of its divisors is an integer number (1040564).

Almost surely, 2^3121689 is an apocalyptic number.

It is an amenable number.

3121689 is a deficient number, since it is larger than the sum of its proper divisors (1040567).

3121689 is a wasteful number, since it uses less digits than its factorization.

3121689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1040566.

The product of its digits is 2592, while the sum is 30.

The square root of 3121689 is about 1766.8302125558. The cubic root of 3121689 is about 146.1492344095.

The spelling of 3121689 in words is "three million, one hundred twenty-one thousand, six hundred eighty-nine".