406635666 has 8 divisors (see below), whose sum is σ = 813271344. Its totient is φ = 135545220.

The previous prime is 406635641. The next prime is 406635683. The reversal of 406635666 is 666536604.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

406635666 is an admirable number.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33886300 + ... + 33886311.

It is an arithmetic number, because the mean of its divisors is an integer number (101658918).

Almost surely, 2^406635666 is an apocalyptic number.

406635666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

406635666 is a wasteful number, since it uses less digits than its factorization.

406635666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67772616.

The product of its (nonzero) digits is 466560, while the sum is 42.

The square root of 406635666 is about 20165.2092972029. The cubic root of 406635666 is about 740.8583089278.

The spelling of 406635666 in words is "four hundred six million, six hundred thirty-five thousand, six hundred sixty-six".