3151921 has 4 divisors (see below), whose sum is σ = 3195172. Its totient is φ = 3108672.

The previous prime is 3151913. The next prime is 3151927. The reversal of 3151921 is 1291513.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1291513 = 47 ⋅27479.

It can be written as a sum of positive squares in 2 ways, for example, as 1852321 + 1299600 = 1361^2 + 1140^2 .

It is a cyclic number.

It is not a de Polignac number, because 3151921 - 2³ = 3151913 is a prime.

It is a Duffinian number.

3151921 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 3151892 and 3151901.

It is not an unprimeable number, because it can be changed into a prime (3151927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21516 + ... + 21661.

It is an arithmetic number, because the mean of its divisors is an integer number (798793).

Almost surely, 2^3151921 is an apocalyptic number.

It is an amenable number.

3151921 is a deficient number, since it is larger than the sum of its proper divisors (43251).

3151921 is an equidigital number, since it uses as much as digits as its factorization.

3151921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43250.

The product of its digits is 270, while the sum is 22.

The square root of 3151921 is about 1775.3650328876. The cubic root of 3151921 is about 146.6195136529.

The spelling of 3151921 in words is "three million, one hundred fifty-one thousand, nine hundred twenty-one".