249563821 has 16 divisors (see below), whose sum is σ = 279745200. Its totient is φ = 222366144.

The previous prime is 249563789. The next prime is 249563849. The reversal of 249563821 is 128365942.

It can be written as a sum of positive squares in 8 ways, for example, as 128255625 + 121308196 = 11325^2 + 11014^2 .

It is not a de Polignac number, because 249563821 - 2⁵ = 249563789 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 (249563851) 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 15 ways as a sum of consecutive naturals, for example, 61755 + ... + 65671.

It is an arithmetic number, because the mean of its divisors is an integer number (17484075).

Almost surely, 2^249563821 is an apocalyptic number.

It is an amenable number.

249563821 is a deficient number, since it is larger than the sum of its proper divisors (30181379).

249563821 is an equidigital number, since it uses as much as digits as its factorization.

249563821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3985 (or 3959 counting only the distinct ones).

The product of its digits is 103680, while the sum is 40.

The square root of 249563821 is about 15797.5890882122. The cubic root of 249563821 is about 629.5939442692.

The spelling of 249563821 in words is "two hundred forty-nine million, five hundred sixty-three thousand, eight hundred twenty-one".