666191736 has 256 divisors, whose sum is σ = 2228428800. Its totient is φ = 180403200.

The previous prime is 666191731. The next prime is 666191749. The reversal of 666191736 is 637191666.

It is a super-2 number, since 2×666191736² = 887622858229387392, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 666191691 and 666191700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666191731) 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 63 ways as a sum of consecutive naturals, for example, 2859076 + ... + 2859308.

It is an arithmetic number, because the mean of its divisors is an integer number (8704800).

Almost surely, 2^666191736 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 666191736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1114214400).

666191736 is an abundant number, since it is smaller than the sum of its proper divisors (1562237064).

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

666191736 is a wasteful number, since it uses less digits than its factorization.

666191736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347 (or 337 counting only the distinct ones).

The product of its digits is 244944, while the sum is 45.

The square root of 666191736 is about 25810.6903433442. The cubic root of 666191736 is about 873.3729703795.

The spelling of 666191736 in words is "six hundred sixty-six million, one hundred ninety-one thousand, seven hundred thirty-six".