666426555 has 32 divisors (see below), whose sum is σ = 1202457600. Its totient is φ = 350117856.

The previous prime is 666426529. The next prime is 666426557. The reversal of 666426555 is 555624666.

It is a happy number.

It is not a de Polignac number, because 666426555 - 2⁹ = 666426043 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 666426555.

It is not an unprimeable number, because it can be changed into a prime (666426557) 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 31 ways as a sum of consecutive naturals, for example, 27795 + ... + 45884.

It is an arithmetic number, because the mean of its divisors is an integer number (37576800).

Almost surely, 2^666426555 is an apocalyptic number.

666426555 is a deficient number, since it is larger than the sum of its proper divisors (536031045).

666426555 is a wasteful number, since it uses less digits than its factorization.

666426555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73760 (or 73754 counting only the distinct ones).

The product of its digits is 1296000, while the sum is 45.

The square root of 666426555 is about 25815.2388135380. The cubic root of 666426555 is about 873.4755737118.

The spelling of 666426555 in words is "six hundred sixty-six million, four hundred twenty-six thousand, five hundred fifty-five".