666622555 has 4 divisors (see below), whose sum is σ = 799947072. Its totient is φ = 533298040.

The previous prime is 666622531. The next prime is 666622559. The reversal of 666622555 is 555226666.

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

It is not a de Polignac number, because 666622555 - 2⁷ = 666622427 is a prime.

It is a Duffinian number.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (666622559) 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, 66662251 + ... + 66662260.

It is an arithmetic number, because the mean of its divisors is an integer number (199986768).

Almost surely, 2^666622555 is an apocalyptic number.

666622555 is a deficient number, since it is larger than the sum of its proper divisors (133324517).

666622555 is a wasteful number, since it uses less digits than its factorization.

666622555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133324516.

The product of its digits is 648000, while the sum is 43.

The square root of 666622555 is about 25819.0347418334. The cubic root of 666622555 is about 873.5611967662.

The spelling of 666622555 in words is "six hundred sixty-six million, six hundred twenty-two thousand, five hundred fifty-five".