66851988 has 48 divisors (see below), whose sum is σ = 179297664. Its totient is φ = 18990720.

The previous prime is 66851987. The next prime is 66852029. The reversal of 66851988 is 88915866.

66851988 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 66851988.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66851987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13006 + ... + 17402.

It is an arithmetic number, because the mean of its divisors is an integer number (3735368).

Almost surely, 2^66851988 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66851988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89648832).

66851988 is an abundant number, since it is smaller than the sum of its proper divisors (112445676).

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

66851988 is a wasteful number, since it uses less digits than its factorization.

66851988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4592 (or 4590 counting only the distinct ones).

The product of its digits is 829440, while the sum is 51.

The square root of 66851988 is about 8176.3065011043. The cubic root of 66851988 is about 405.8555060242.

The spelling of 66851988 in words is "sixty-six million, eight hundred fifty-one thousand, nine hundred eighty-eight".