6557971644 has 216 divisors, whose sum is σ = 19750768128. Its totient is φ = 1828915200.

The previous prime is 6557971643. The next prime is 6557971703. The reversal of 6557971644 is 4461797556.

6557971644 is a `hidden beast` number, since 6 + 5 + 579 + 7 + 1 + 64 + 4 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6557971643) 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 71 ways as a sum of consecutive naturals, for example, 16353844 + ... + 16354244.

Almost surely, 2^6557971644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6557971644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9875384064).

6557971644 is an abundant number, since it is smaller than the sum of its proper divisors (13192796484).

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

6557971644 is a wasteful number, since it uses less digits than its factorization.

6557971644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 625 (or 613 counting only the distinct ones).

The product of its digits is 6350400, while the sum is 54.

The square root of 6557971644 is about 80981.3042868538. The cubic root of 6557971644 is about 1871.7873655866.

The spelling of 6557971644 in words is "six billion, five hundred fifty-seven million, nine hundred seventy-one thousand, six hundred forty-four".