6657997566 has 64 divisors (see below), whose sum is σ = 14822424576. Its totient is φ = 1976805600.

The previous prime is 6657997517. The next prime is 6657997573.

6657997566 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a junction number, because it is equal to n+sod(n) for n = 6657997497 and 6657997506.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 840661 + ... + 848543.

It is an arithmetic number, because the mean of its divisors is an integer number (231600384).

Almost surely, 2^6657997566 is an apocalyptic number.

6657997566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 6657997566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7411212288).

6657997566 is an abundant number, since it is smaller than the sum of its proper divisors (8164427010).

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

6657997566 is a wasteful number, since it uses less digits than its factorization.

6657997566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8157.

The product of its digits is 128595600, while the sum is 66.

The square root of 6657997566 is about 81596.5536404571. The cubic root of 6657997566 is about 1881.2559102900.

The spelling of 6657997566 in words is "six billion, six hundred fifty-seven million, nine hundred ninety-seven thousand, five hundred sixty-six".