666101605 has 32 divisors (see below), whose sum is σ = 894225024. Its totient is φ = 473147136.

The previous prime is 666101603. The next prime is 666101629. The reversal of 666101605 is 506101666.

It is a cyclic number.

It is not a de Polignac number, because 666101605 - 2¹ = 666101603 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666101603) 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, 185487 + ... + 189043.

It is an arithmetic number, because the mean of its divisors is an integer number (27944532).

Almost surely, 2^666101605 is an apocalyptic number.

666101605 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

666101605 is a deficient number, since it is larger than the sum of its proper divisors (228123419).

666101605 is a wasteful number, since it uses less digits than its factorization.

666101605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3685.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 666101605 is about 25808.9442829419. The cubic root of 666101605 is about 873.3335815544. Note that the first 3 decimals are identical.

The spelling of 666101605 in words is "six hundred sixty-six million, one hundred one thousand, six hundred five".