66965667840 has 612 divisors, whose sum is σ = 249331644744. Its totient is φ = 17241735168.

The previous prime is 66965667833. The next prime is 66965667877. The reversal of 66965667840 is 4876656966.

66965667840 is a `hidden beast` number, since 6 + 69 + 6 + 566 + 7 + 8 + 4 + 0 = 666.

It is a super-3 number, since 3×66965667840³ (a number of 33 digits) contains 333 as substring.

It is a nialpdrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2309160946 + ... + 2309160974.

Almost surely, 2^66965667840 is an apocalyptic number.

66965667840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66965667840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124665822372).

66965667840 is an abundant number, since it is smaller than the sum of its proper divisors (182365976904).

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

66965667840 is an frugal number, since it uses more digits than its factorization.

66965667840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110 (or 39 counting only the distinct ones).

The product of its (nonzero) digits is 78382080, while the sum is 63.

The spelling of 66965667840 in words is "sixty-six billion, nine hundred sixty-five million, six hundred sixty-seven thousand, eight hundred forty".