6821603649 has 189 divisors, whose sum is σ = 13126384593. Its totient is φ = 3532337424.

The previous prime is 6821603623. The next prime is 6821603653. The reversal of 6821603649 is 9463061286.

The square root of 6821603649 is 82593.

It is a perfect power (a square), and thus also a powerful number.

It is a tau number, because it is divible by the number of its divisors (189).

It is not a de Polignac number, because 6821603649 - 2⁷ = 6821603521 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6821603609) by changing a digit.

It is a polite number, since it can be written in 188 ways as a sum of consecutive naturals, for example, 296591452 + ... + 296591474.

Almost surely, 2^6821603649 is an apocalyptic number.

6821603649 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

6821603649 is the 82593-rd square number.

6821603649 is the 41297-th centered octagonal number.

It is an amenable number.

6821603649 is a deficient number, since it is larger than the sum of its proper divisors (6304780944).

6821603649 is an equidigital number, since it uses as much as digits as its factorization.

6821603649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116 (or 52 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The cubic root of 6821603649 is about 1896.5406720947.

The spelling of 6821603649 in words is "six billion, eight hundred twenty-one million, six hundred three thousand, six hundred forty-nine".