66356725806 has 192 divisors, whose sum is σ = 170299584000. Its totient is φ = 18663853824.

The previous prime is 66356725789. The next prime is 66356725823. The reversal of 66356725806 is 60852765366.

It is a happy number.

66356725806 is a `hidden beast` number, since 6 + 6 + 3 + 56 + 7 + 2 + 580 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (66356725789) and next prime (66356725823).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 158369065 + ... + 158369483.

It is an arithmetic number, because the mean of its divisors is an integer number (886977000).

Almost surely, 2^66356725806 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66356725806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85149792000).

66356725806 is an abundant number, since it is smaller than the sum of its proper divisors (103942858194).

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

66356725806 is a wasteful number, since it uses less digits than its factorization.

66356725806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 788 (or 771 counting only the distinct ones).

The product of its (nonzero) digits is 10886400, while the sum is 54.

The spelling of 66356725806 in words is "sixty-six billion, three hundred fifty-six million, seven hundred twenty-five thousand, eight hundred six".