2728521 has 12 divisors (see below), whose sum is σ = 3996148. Its totient is φ = 1793664.

The previous prime is 2728519. The next prime is 2728541. The reversal of 2728521 is 1258272.

It can be written as a sum of positive squares in 2 ways, for example, as 585225 + 2143296 = 765^2 + 1464^2 .

It is not a de Polignac number, because 2728521 - 2¹ = 2728519 is a prime.

It is a Duffinian number.

2728521 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2728541) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1420 + ... + 2733.

2^2728521 is an apocalyptic number.

It is an amenable number.

2728521 is a deficient number, since it is larger than the sum of its proper divisors (1267627).

2728521 is a wasteful number, since it uses less digits than its factorization.

2728521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4232 (or 4229 counting only the distinct ones).

The product of its digits is 2240, while the sum is 27.

The square root of 2728521 is about 1651.8235377909. The cubic root of 2728521 is about 139.7362551459.

It can be divided in two parts, 27285 and 21, that multiplied together give a triangular number (572985 = T₁₀₇₀).

The spelling of 2728521 in words is "two million, seven hundred twenty-eight thousand, five hundred twenty-one".