666405606 has 16 divisors (see below), whose sum is σ = 1349683200. Its totient is φ = 219323208.

The previous prime is 666405599. The next prime is 666405613. The reversal of 666405606 is 606504666.

It is an interprime number because it is at equal distance from previous prime (666405599) and next prime (666405613).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 702486 + ... + 703433.

It is an arithmetic number, because the mean of its divisors is an integer number (84355200).

Almost surely, 2^666405606 is an apocalyptic number.

666405606 is an abundant number, since it is smaller than the sum of its proper divisors (683277594).

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

666405606 is a wasteful number, since it uses less digits than its factorization.

666405606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1406003.

The product of its (nonzero) digits is 155520, while the sum is 39.

The square root of 666405606 is about 25814.8330616334. The cubic root of 666405606 is about 873.4664210996.

The spelling of 666405606 in words is "six hundred sixty-six million, four hundred five thousand, six hundred six".