2720721 has 16 divisors (see below), whose sum is σ = 3774464. Its totient is φ = 1741824.

The previous prime is 2720717. The next prime is 2720723. The reversal of 2720721 is 1270272.

It is not a de Polignac number, because 2720721 - 2² = 2720717 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2720723) 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, 14001 + ... + 14193.

It is an arithmetic number, because the mean of its divisors is an integer number (235904).

2^2720721 is an apocalyptic number.

It is an amenable number.

2720721 is a deficient number, since it is larger than the sum of its proper divisors (1053743).

2720721 is a wasteful number, since it uses less digits than its factorization.

2720721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360.

The product of its (nonzero) digits is 392, while the sum is 21.

The square root of 2720721 is about 1649.4608209958. The cubic root of 2720721 is about 139.6029737765.

Adding to 2720721 its reverse (1270272), we get a palindrome (3990993).

The spelling of 2720721 in words is "two million, seven hundred twenty thousand, seven hundred twenty-one".