66420555 has 8 divisors (see below), whose sum is σ = 106272912. Its totient is φ = 35424288.

The previous prime is 66420553. The next prime is 66420559. The reversal of 66420555 is 55502466.

It is a happy number.

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

It is not a de Polignac number, because 66420555 - 2¹ = 66420553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66420553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2214004 + ... + 2214033.

It is an arithmetic number, because the mean of its divisors is an integer number (13284114).

Almost surely, 2^66420555 is an apocalyptic number.

66420555 is a deficient number, since it is larger than the sum of its proper divisors (39852357).

66420555 is a wasteful number, since it uses less digits than its factorization.

66420555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4428045.

The product of its (nonzero) digits is 36000, while the sum is 33.

The square root of 66420555 is about 8149.8806739731. The cubic root of 66420555 is about 404.9805508112.

The spelling of 66420555 in words is "sixty-six million, four hundred twenty thousand, five hundred fifty-five".