2897821 has 4 divisors (see below), whose sum is σ = 2910492. Its totient is φ = 2885152.

The previous prime is 2897819. The next prime is 2897827. The reversal of 2897821 is 1287982.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1287982 = 2 ⋅643991.

It can be written as a sum of positive squares in 2 ways, for example, as 302500 + 2595321 = 550^2 + 1611^2 .

It is a cyclic number.

It is not a de Polignac number, because 2897821 - 2¹ = 2897819 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 (2897827) 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, 5986 + ... + 6451.

It is an arithmetic number, because the mean of its divisors is an integer number (727623).

2^2897821 is an apocalyptic number.

It is an amenable number.

2897821 is a deficient number, since it is larger than the sum of its proper divisors (12671).

2897821 is a wasteful number, since it uses less digits than its factorization.

2897821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12670.

The product of its digits is 16128, while the sum is 37.

The square root of 2897821 is about 1702.2987399396. The cubic root of 2897821 is about 142.5685891210.

The spelling of 2897821 in words is "two million, eight hundred ninety-seven thousand, eight hundred twenty-one".