2781321 has 16 divisors (see below), whose sum is σ = 3908736. Its totient is φ = 1755776.

The previous prime is 2781313. The next prime is 2781329. The reversal of 2781321 is 1231872.

It is an interprime number because it is at equal distance from previous prime (2781313) and next prime (2781329).

It is a cyclic number.

It is not a de Polignac number, because 2781321 - 2³ = 2781313 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2781291 and 2781300.

It is not an unprimeable number, because it can be changed into a prime (2781329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11821 + ... + 12053.

It is an arithmetic number, because the mean of its divisors is an integer number (244296).

2^2781321 is an apocalyptic number.

It is an amenable number.

2781321 is a deficient number, since it is larger than the sum of its proper divisors (1127415).

2781321 is a wasteful number, since it uses less digits than its factorization.

2781321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432.

The product of its digits is 672, while the sum is 24.

The square root of 2781321 is about 1667.7292945799. The cubic root of 2781321 is about 140.6318548757.

The spelling of 2781321 in words is "two million, seven hundred eighty-one thousand, three hundred twenty-one".