2729721 has 4 divisors (see below), whose sum is σ = 3639632. Its totient is φ = 1819812.

The previous prime is 2729717. The next prime is 2729723. The reversal of 2729721 is 1279272.

It is a happy number.

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 2729721 - 2² = 2729717 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 (2729723) 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 3 ways as a sum of consecutive naturals, for example, 454951 + ... + 454956.

It is an arithmetic number, because the mean of its divisors is an integer number (909908).

2^2729721 is an apocalyptic number.

It is an amenable number.

2729721 is a deficient number, since it is larger than the sum of its proper divisors (909911).

2729721 is an equidigital number, since it uses as much as digits as its factorization.

2729721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 909910.

The product of its digits is 3528, while the sum is 30.

The square root of 2729721 is about 1652.1867327878. The cubic root of 2729721 is about 139.7567374182.

The spelling of 2729721 in words is "two million, seven hundred twenty-nine thousand, seven hundred twenty-one".