648249221 has 4 divisors (see below), whose sum is σ = 648393600. Its totient is φ = 648104844.

The previous prime is 648249193. The next prime is 648249229. The reversal of 648249221 is 122942846.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-648249221 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 (648249229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65231 + ... + 74508.

It is an arithmetic number, because the mean of its divisors is an integer number (162098400).

Almost surely, 2^648249221 is an apocalyptic number.

It is an amenable number.

648249221 is a deficient number, since it is larger than the sum of its proper divisors (144379).

648249221 is a wasteful number, since it uses less digits than its factorization.

648249221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144378.

The product of its digits is 55296, while the sum is 38.

The square root of 648249221 is about 25460.7388148891. The cubic root of 648249221 is about 865.4606658912.

The spelling of 648249221 in words is "six hundred forty-eight million, two hundred forty-nine thousand, two hundred twenty-one".