8123191566 has 256 divisors, whose sum is σ = 21842472960. Its totient is φ = 1958584320.

The previous prime is 8123191541. The next prime is 8123191577. The reversal of 8123191566 is 6651913218.

8123191566 = 386² + 387² + ... + 2901².

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 17620576 + ... + 17621036.

It is an arithmetic number, because the mean of its divisors is an integer number (85322160).

Almost surely, 2^8123191566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8123191566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10921236480).

8123191566 is an abundant number, since it is smaller than the sum of its proper divisors (13719281394).

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

8123191566 is a wasteful number, since it uses less digits than its factorization.

8123191566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579.

The product of its digits is 77760, while the sum is 42.

The square root of 8123191566 is about 90128.7499414033. The cubic root of 8123191566 is about 2010.2137150545.

The spelling of 8123191566 in words is "eight billion, one hundred twenty-three million, one hundred ninety-one thousand, five hundred sixty-six".