66572640 has 144 divisors (see below), whose sum is σ = 230329008. Its totient is φ = 17507328.

The previous prime is 66572621. The next prime is 66572641. The reversal of 66572640 is 4627566.

66572640 is a `hidden beast` number, since 6 + 6 + 5 + 7 + 2 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 66572595 and 66572604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66572641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 119242 + ... + 119798.

It is an arithmetic number, because the mean of its divisors is an integer number (1599507).

Almost surely, 2^66572640 is an apocalyptic number.

66572640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66572640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115164504).

66572640 is an abundant number, since it is smaller than the sum of its proper divisors (163756368).

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

66572640 is a wasteful number, since it uses less digits than its factorization.

66572640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 661 (or 650 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 66572640 is about 8159.2058437081. The cubic root of 66572640 is about 405.2894136200.

The spelling of 66572640 in words is "sixty-six million, five hundred seventy-two thousand, six hundred forty".