66977763840 has 640 divisors, whose sum is σ = 258620947200. Its totient is φ = 16332226560.

The previous prime is 66977763833. The next prime is 66977763859. The reversal of 66977763840 is 4836777966.

It is a tau number, because it is divible by the number of its divisors (640).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 117711076 + ... + 117711644.

It is an arithmetic number, because the mean of its divisors is an integer number (404095230).

Almost surely, 2^66977763840 is an apocalyptic number.

66977763840 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 66977763840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129310473600).

66977763840 is an abundant number, since it is smaller than the sum of its proper divisors (191643183360).

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

66977763840 is a wasteful number, since it uses less digits than its factorization.

66977763840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 745 (or 723 counting only the distinct ones).

The product of its (nonzero) digits is 64012032, while the sum is 63.

The spelling of 66977763840 in words is "sixty-six billion, nine hundred seventy-seven million, seven hundred sixty-three thousand, eight hundred forty".