2745821 has 4 divisors (see below), whose sum is σ = 2957052. Its totient is φ = 2534592.

The previous prime is 2745797. The next prime is 2745829. The reversal of 2745821 is 1285472.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1092025 + 1653796 = 1045^2 + 1286^2 .

It is a cyclic number.

It is not a de Polignac number, because 2745821 - 2¹⁴ = 2729437 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 (2745829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105596 + ... + 105621.

It is an arithmetic number, because the mean of its divisors is an integer number (739263).

2^2745821 is an apocalyptic number.

It is an amenable number.

2745821 is a deficient number, since it is larger than the sum of its proper divisors (211231).

2745821 is a wasteful number, since it uses less digits than its factorization.

2745821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211230.

The product of its digits is 4480, while the sum is 29.

The square root of 2745821 is about 1657.0519002131. The cubic root of 2745821 is about 140.0309625395.

The spelling of 2745821 in words is "two million, seven hundred forty-five thousand, eight hundred twenty-one".