2646721 has 16 divisors (see below), whose sum is σ = 3392640. Its totient is φ = 2004480.

The previous prime is 2646671. The next prime is 2646733. The reversal of 2646721 is 1276462.

It is a cyclic number.

It is not a de Polignac number, because 2646721 - 2¹³ = 2638529 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2646721.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2640721) 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, 2385 + ... + 3313.

It is an arithmetic number, because the mean of its divisors is an integer number (212040).

2^2646721 is an apocalyptic number.

It is an amenable number.

2646721 is a deficient number, since it is larger than the sum of its proper divisors (745919).

2646721 is a wasteful number, since it uses less digits than its factorization.

2646721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 984.

The product of its digits is 4032, while the sum is 28.

The square root of 2646721 is about 1626.8746110257. The cubic root of 2646721 is about 138.3256504499.

Adding to 2646721 its product of digits (4032), we get a triangular number (2650753 = T₂₃₀₂).

The spelling of 2646721 in words is "two million, six hundred forty-six thousand, seven hundred twenty-one".