66028555 has 4 divisors (see below), whose sum is σ = 79234272. Its totient is φ = 52822840.

The previous prime is 66028531. The next prime is 66028559. The reversal of 66028555 is 55582066.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 66028555 - 2²¹ = 63931403 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66028559) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6602851 + ... + 6602860.

It is an arithmetic number, because the mean of its divisors is an integer number (19808568).

Almost surely, 2^66028555 is an apocalyptic number.

66028555 is a deficient number, since it is larger than the sum of its proper divisors (13205717).

66028555 is a wasteful number, since it uses less digits than its factorization.

66028555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13205716.

The product of its (nonzero) digits is 72000, while the sum is 37.

The square root of 66028555 is about 8125.7956533499. The cubic root of 66028555 is about 404.1822752796.

The spelling of 66028555 in words is "sixty-six million, twenty-eight thousand, five hundred fifty-five".