2981721 has 4 divisors (see below), whose sum is σ = 3975632. Its totient is φ = 1987812.

The previous prime is 2981711. The next prime is 2981753. The reversal of 2981721 is 1271892.

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.

It is not a de Polignac number, because 2981721 - 2¹⁰ = 2980697 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2981711) 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, 496951 + ... + 496956.

It is an arithmetic number, because the mean of its divisors is an integer number (993908).

2^2981721 is an apocalyptic number.

It is an amenable number.

2981721 is a deficient number, since it is larger than the sum of its proper divisors (993911).

2981721 is an equidigital number, since it uses as much as digits as its factorization.

2981721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 993910.

The product of its digits is 2016, while the sum is 30.

The square root of 2981721 is about 1726.7660524808. The cubic root of 2981721 is about 143.9314391987.

The spelling of 2981721 in words is "two million, nine hundred eighty-one thousand, seven hundred twenty-one".