2152821 has 16 divisors (see below), whose sum is σ = 3170880. Its totient is φ = 1288320.

The previous prime is 2152819. The next prime is 2152831. The reversal of 2152821 is 1282512.

It is a happy number.

2152821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2152821 - 2¹ = 2152819 is a prime.

It is an Ulam number.

2152821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2152811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2571 + ... + 3303.

It is an arithmetic number, because the mean of its divisors is an integer number (198180).

2^2152821 is an apocalyptic number.

It is an amenable number.

2152821 is a deficient number, since it is larger than the sum of its proper divisors (1018059).

2152821 is a wasteful number, since it uses less digits than its factorization.

2152821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 836.

The product of its digits is 320, while the sum is 21.

The square root of 2152821 is about 1467.2494675412. The cubic root of 2152821 is about 129.1227123886.

The spelling of 2152821 in words is "two million, one hundred fifty-two thousand, eight hundred twenty-one".