66440772 has 18 divisors (see below), whose sum is σ = 167947598. Its totient is φ = 22146912.

The previous prime is 66440771. The next prime is 66440779. The reversal of 66440772 is 27704466.

66440772 is a `hidden beast` number, since 6 + 644 + 0 + 7 + 7 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 61214976 + 5225796 = 7824^2 + 2286^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 1845577 = 66440772 / (6 + 6 + 4 + 4 + 0 + 7 + 7 + 2).

It is not an unprimeable number, because it can be changed into a prime (66440771) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 922753 + ... + 922824.

Almost surely, 2^66440772 is an apocalyptic number.

It is an amenable number.

66440772 is an abundant number, since it is smaller than the sum of its proper divisors (101506826).

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

66440772 is a wasteful number, since it uses less digits than its factorization.

66440772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1845587 (or 1845582 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 36.

The square root of 66440772 is about 8151.1209045137. The cubic root of 66440772 is about 405.0216357897.

The spelling of 66440772 in words is "sixty-six million, four hundred forty thousand, seven hundred seventy-two".