6421618225 has 81 divisors (see below), whose sum is σ = 9240471723. Its totient is φ = 4423452000.

The previous prime is 6421618187. The next prime is 6421618249. The reversal of 6421618225 is 5228161246.

The square root of 6421618225 is 80135.

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

It can be written as a sum of positive squares in only one way, i.e., 2311782561 + 4109835664 = 48081^2 + 64108^2 .

It is not a de Polignac number, because 6421618225 - 2¹¹ = 6421616177 is a prime.

It is an unprimeable number.

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 80 ways as a sum of consecutive naturals, for example, 136630152 + ... + 136630198.

Almost surely, 2^6421618225 is an apocalyptic number.

6421618225 is the 80135-th square number.

6421618225 is the 40068-th centered octagonal number.

It is an amenable number.

6421618225 is a deficient number, since it is larger than the sum of its proper divisors (2818853498).

6421618225 is a wasteful number, since it uses less digits than its factorization.

6421618225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188 (or 94 counting only the distinct ones).

The product of its digits is 46080, while the sum is 37.

The cubic root of 6421618225 is about 1858.7236614093.

The spelling of 6421618225 in words is "six billion, four hundred twenty-one million, six hundred eighteen thousand, two hundred twenty-five".