666563405 has 16 divisors (see below), whose sum is σ = 828334080. Its totient is φ = 514317888.

The previous prime is 666563357. The next prime is 666563413. The reversal of 666563405 is 504365666.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 666563405 - 2¹⁸ = 666301261 is a prime.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 184244 + ... + 187826.

It is an arithmetic number, because the mean of its divisors is an integer number (51770880).

Almost surely, 2^666563405 is an apocalyptic number.

It is an amenable number.

666563405 is a deficient number, since it is larger than the sum of its proper divisors (161770675).

666563405 is a wasteful number, since it uses less digits than its factorization.

666563405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4900.

The product of its (nonzero) digits is 388800, while the sum is 41.

The square root of 666563405 is about 25817.8892437008. The cubic root of 666563405 is about 873.5353587200.

The spelling of 666563405 in words is "six hundred sixty-six million, five hundred sixty-three thousand, four hundred five".