66816723456 has 240 divisors, whose sum is σ = 227498439168. Its totient is φ = 18474393600.

The previous prime is 66816723409. The next prime is 66816723461. The reversal of 66816723456 is 65432761866.

66816723456 is a `hidden beast` number, since 6 + 6 + 8 + 167 + 23 + 456 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 966526 + ... + 1033346.

Almost surely, 2^66816723456 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 66816723456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113749219584).

66816723456 is an abundant number, since it is smaller than the sum of its proper divisors (160681715712).

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

66816723456 is a wasteful number, since it uses less digits than its factorization.

66816723456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66883 (or 66864 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 54.

The spelling of 66816723456 in words is "sixty-six billion, eight hundred sixteen million, seven hundred twenty-three thousand, four hundred fifty-six".