66623555 has 8 divisors (see below), whose sum is σ = 81807792. Its totient is φ = 52059168.

The previous prime is 66623551. The next prime is 66623591. The reversal of 66623555 is 55532666.

66623555 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66623555 - 2² = 66623551 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66623551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154724 + ... + 155153.

It is an arithmetic number, because the mean of its divisors is an integer number (10225974).

Almost surely, 2^66623555 is an apocalyptic number.

66623555 is a deficient number, since it is larger than the sum of its proper divisors (15184237).

66623555 is a wasteful number, since it uses less digits than its factorization.

66623555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309925.

The product of its digits is 162000, while the sum is 38.

The square root of 66623555 is about 8162.3253426949. The cubic root of 66623555 is about 405.3927095690.

The spelling of 66623555 in words is "sixty-six million, six hundred twenty-three thousand, five hundred fifty-five".