2720639 has 4 divisors (see below), whose sum is σ = 2724000. Its totient is φ = 2717280.

The previous prime is 2720623. The next prime is 2720671. The reversal of 2720639 is 9360272.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2720639 - 2⁴ = 2720623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2720609) 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, 362 + ... + 2360.

It is an arithmetic number, because the mean of its divisors is an integer number (681000).

2^2720639 is an apocalyptic number.

2720639 is a deficient number, since it is larger than the sum of its proper divisors (3361).

2720639 is a wasteful number, since it uses less digits than its factorization.

2720639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3360.

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 2720639 is about 1649.4359642011. The cubic root of 2720639 is about 139.6015712611.

The spelling of 2720639 in words is "two million, seven hundred twenty thousand, six hundred thirty-nine".