66897990720 has 1120 divisors, whose sum is σ = 279615473280. Its totient is φ = 15009546240.

The previous prime is 66897990697. The next prime is 66897990727. The reversal of 66897990720 is 2709979866.

It is a super-2 number, since 2×66897990720² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66897990727) 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 159 ways as a sum of consecutive naturals, for example, 287115724 + ... + 287115956.

Almost surely, 2^66897990720 is an apocalyptic number.

66897990720 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 66897990720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139807736640).

66897990720 is an abundant number, since it is smaller than the sum of its proper divisors (212717482560).

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

66897990720 is a wasteful number, since it uses less digits than its factorization.

66897990720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 20575296, while the sum is 63.

The spelling of 66897990720 in words is "sixty-six billion, eight hundred ninety-seven million, nine hundred ninety thousand, seven hundred twenty".