666026555 has 4 divisors (see below), whose sum is σ = 799231872. Its totient is φ = 532821240.

The previous prime is 666026549. The next prime is 666026579. The reversal of 666026555 is 555620666.

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

It is not a de Polignac number, because 666026555 - 2¹⁰ = 666025531 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66602651 + ... + 66602660.

It is an arithmetic number, because the mean of its divisors is an integer number (199807968).

Almost surely, 2^666026555 is an apocalyptic number.

666026555 is a deficient number, since it is larger than the sum of its proper divisors (133205317).

666026555 is a wasteful number, since it uses less digits than its factorization.

666026555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133205316.

The product of its (nonzero) digits is 324000, while the sum is 41.

The square root of 666026555 is about 25807.4902886739. The cubic root of 666026555 is about 873.3007806791.

The spelling of 666026555 in words is "six hundred sixty-six million, twenty-six thousand, five hundred fifty-five".