2681721 has 24 divisors (see below), whose sum is σ = 4623840. Its totient is φ = 1531656.

The previous prime is 2681719. The next prime is 2681729. The reversal of 2681721 is 1271862.

It is not a de Polignac number, because 2681721 - 2¹ = 2681719 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2681729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 310 + ... + 2336.

It is an arithmetic number, because the mean of its divisors is an integer number (192660).

2^2681721 is an apocalyptic number.

2681721 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2681721 is a deficient number, since it is larger than the sum of its proper divisors (1942119).

2681721 is a wasteful number, since it uses less digits than its factorization.

2681721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2050 (or 2037 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 2681721 is about 1637.5961040501. The cubic root of 2681721 is about 138.9327176402.

The spelling of 2681721 in words is "two million, six hundred eighty-one thousand, seven hundred twenty-one".