666206405 has 16 divisors (see below), whose sum is σ = 842160000. Its totient is φ = 504532800.

The previous prime is 666206381. The next prime is 666206467. The reversal of 666206405 is 504602666.

It is not a de Polignac number, because 666206405 - 2¹² = 666202309 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 240971 + ... + 243719.

It is an arithmetic number, because the mean of its divisors is an integer number (52635000).

Almost surely, 2^666206405 is an apocalyptic number.

It is an amenable number.

666206405 is a deficient number, since it is larger than the sum of its proper divisors (175953595).

666206405 is a wasteful number, since it uses less digits than its factorization.

666206405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5324.

The product of its (nonzero) digits is 51840, while the sum is 35.

The square root of 666206405 is about 25810.9745069806. The cubic root of 666206405 is about 873.3793806532.

The spelling of 666206405 in words is "six hundred sixty-six million, two hundred six thousand, four hundred five".