6557220864 has 270 divisors, whose sum is σ = 19992522914. Its totient is φ = 2149908480.

The previous prime is 6557220821. The next prime is 6557220881. The reversal of 6557220864 is 4680227556.

It can be written as a sum of positive squares in only one way, i.e., 3869835264 + 2687385600 = 62208^2 + 51840^2 .

It is a congruent number.

It is an unprimeable number.

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 17 ways as a sum of consecutive naturals, for example, 107495394 + ... + 107495454.

Almost surely, 2^6557220864 is an apocalyptic number.

6557220864 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6557220864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9996261457).

6557220864 is an abundant number, since it is smaller than the sum of its proper divisors (13435302050).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6557220864 is an frugal number, since it uses more digits than its factorization.

6557220864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 66 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 45.

The square root of 6557220864 is about 80976.6686398002. The cubic root of 6557220864 is about 1871.7159332278.

It can be divided in two parts, 65572 and 20864, that added together give a square (86436 = 294²).

The spelling of 6557220864 in words is "six billion, five hundred fifty-seven million, two hundred twenty thousand, eight hundred sixty-four".