66640224 has 96 divisors (see below), whose sum is σ = 201712896. Its totient is φ = 18869760.

The previous prime is 66640199. The next prime is 66640229. The reversal of 66640224 is 42204666.

It is a tau number, because it is divible by the number of its divisors (96).

It is a junction number, because it is equal to n+sod(n) for n = 66640191 and 66640200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66640229) 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, 87654 + ... + 88410.

It is an arithmetic number, because the mean of its divisors is an integer number (2101176).

Almost surely, 2^66640224 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 66640224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100856448).

66640224 is an abundant number, since it is smaller than the sum of its proper divisors (135072672).

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

66640224 is a wasteful number, since it uses less digits than its factorization.

66640224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908 (or 900 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 66640224 is about 8163.3463726587. The cubic root of 66640224 is about 405.4265160687.

It can be divided in two parts, 6 and 6640224, that multiplied together give a square (39841344 = 6312²).

The spelling of 66640224 in words is "sixty-six million, six hundred forty thousand, two hundred twenty-four".