66801991960 has 32 divisors (see below), whose sum is σ = 163968526800. Its totient is φ = 24291633280.

The previous prime is 66801991951. The next prime is 66801991967. The reversal of 66801991960 is 6919910866.

It is a super-2 number, since 2×66801991960² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66801991967) 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 7 ways as a sum of consecutive naturals, for example, 75910915 + ... + 75911794.

Almost surely, 2^66801991960 is an apocalyptic number.

It is an amenable number.

66801991960 is an abundant number, since it is smaller than the sum of its proper divisors (97166534840).

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

66801991960 is a wasteful number, since it uses less digits than its factorization.

66801991960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151822731 (or 151822727 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 55.

The spelling of 66801991960 in words is "sixty-six billion, eight hundred one million, nine hundred ninety-one thousand, nine hundred sixty".