4891821 has 16 divisors (see below), whose sum is σ = 7154688. Its totient is φ = 2948400.

The previous prime is 4891787. The next prime is 4891823. The reversal of 4891821 is 1281984.

4891821 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 4891821 - 2¹⁹ = 4367533 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4891823) 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, 8670 + ... + 9216.

It is an arithmetic number, because the mean of its divisors is an integer number (447168).

Almost surely, 2^4891821 is an apocalyptic number.

It is an amenable number.

4891821 is a deficient number, since it is larger than the sum of its proper divisors (2262867).

4891821 is a wasteful number, since it uses less digits than its factorization.

4891821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 832.

The product of its digits is 4608, while the sum is 33.

The square root of 4891821 is about 2211.7461427569. The cubic root of 4891821 is about 169.7553690201.

The spelling of 4891821 in words is "four million, eight hundred ninety-one thousand, eight hundred twenty-one".