66561272 has 8 divisors (see below), whose sum is σ = 124802400. Its totient is φ = 33280632.

The previous prime is 66561251. The next prime is 66561277. The reversal of 66561272 is 27216566.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66561277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4160072 + ... + 4160087.

It is an arithmetic number, because the mean of its divisors is an integer number (15600300).

Almost surely, 2^66561272 is an apocalyptic number.

It is an amenable number.

66561272 is a deficient number, since it is larger than the sum of its proper divisors (58241128).

66561272 is a wasteful number, since it uses less digits than its factorization.

66561272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8320165 (or 8320161 counting only the distinct ones).

The product of its digits is 30240, while the sum is 35.

The square root of 66561272 is about 8158.5091775397. The cubic root of 66561272 is about 405.2663431197.

The spelling of 66561272 in words is "sixty-six million, five hundred sixty-one thousand, two hundred seventy-two".