2851821 has 32 divisors (see below), whose sum is σ = 4915200. Its totient is φ = 1600560.

The previous prime is 2851817. The next prime is 2851829. The reversal of 2851821 is 1281582.

It is not a de Polignac number, because 2851821 - 2² = 2851817 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2851829) 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 31 ways as a sum of consecutive naturals, for example, 14836 + ... + 15026.

It is an arithmetic number, because the mean of its divisors is an integer number (153600).

2^2851821 is an apocalyptic number.

2851821 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2851821 is a deficient number, since it is larger than the sum of its proper divisors (2063379).

2851821 is a wasteful number, since it uses less digits than its factorization.

2851821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286 (or 280 counting only the distinct ones).

The product of its digits is 1280, while the sum is 27.

The square root of 2851821 is about 1688.7335491427. The cubic root of 2851821 is about 141.8101841240.

The spelling of 2851821 in words is "two million, eight hundred fifty-one thousand, eight hundred twenty-one".