66706871920 has 80 divisors (see below), whose sum is σ = 168339225600. Its totient is φ = 24436242432.

The previous prime is 66706871849. The next prime is 66706871921. The reversal of 66706871920 is 2917860766.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×66706871920² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66706871921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 120445 + ... + 384604.

It is an arithmetic number, because the mean of its divisors is an integer number (2104240320).

Almost surely, 2^66706871920 is an apocalyptic number.

It is an amenable number.

66706871920 is an abundant number, since it is smaller than the sum of its proper divisors (101632353680).

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

66706871920 is a wasteful number, since it uses less digits than its factorization.

66706871920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505202 (or 505196 counting only the distinct ones).

The product of its (nonzero) digits is 1524096, while the sum is 52.

The spelling of 66706871920 in words is "sixty-six billion, seven hundred six million, eight hundred seventy-one thousand, nine hundred twenty".