66143840 has 96 divisors (see below), whose sum is σ = 181258560. Its totient is φ = 22339584.

The previous prime is 66143839. The next prime is 66143843. The reversal of 66143840 is 4834166.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 66143797 and 66143806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66143843) 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, 81356 + ... + 82164.

It is an arithmetic number, because the mean of its divisors is an integer number (1888110).

Almost surely, 2^66143840 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 66143840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90629280).

66143840 is an abundant number, since it is smaller than the sum of its proper divisors (115114720).

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

66143840 is a wasteful number, since it uses less digits than its factorization.

66143840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 904 (or 896 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 66143840 is about 8132.8863265141. The cubic root of 66143840 is about 404.4173708436.

The spelling of 66143840 in words is "sixty-six million, one hundred forty-three thousand, eight hundred forty".