66573640 has 32 divisors (see below), whose sum is σ = 171190080. Its totient is φ = 22825152.

The previous prime is 66573629. The next prime is 66573641. The reversal of 66573640 is 4637566.

It is a self number, because there is not a number n which added to its sum of digits gives 66573640.

It is not an unprimeable number, because it can be changed into a prime (66573641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 118602 + ... + 119161.

It is an arithmetic number, because the mean of its divisors is an integer number (5349690).

Almost surely, 2^66573640 is an apocalyptic number.

It is an amenable number.

66573640 is an abundant number, since it is smaller than the sum of its proper divisors (104616440).

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

66573640 is a wasteful number, since it uses less digits than its factorization.

66573640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237781 (or 237777 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 37.

The square root of 66573640 is about 8159.2671239518. The cubic root of 66573640 is about 405.2914429190.

It can be divided in two parts, 665 and 73640, that added together give a triangular number (74305 = T₃₈₅).

The spelling of 66573640 in words is "sixty-six million, five hundred seventy-three thousand, six hundred forty".