1205664666 has 16 divisors (see below), whose sum is σ = 2438424000. Its totient is φ = 397372448.

The previous prime is 1205664653. The next prime is 1205664671. The reversal of 1205664666 is 6664665021.

It is a happy 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, 1128366 + ... + 1129433.

It is an arithmetic number, because the mean of its divisors is an integer number (152401500).

Almost surely, 2^1205664666 is an apocalyptic number.

1205664666 is an abundant number, since it is smaller than the sum of its proper divisors (1232759334).

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

1205664666 is a wasteful number, since it uses less digits than its factorization.

1205664666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2257893.

The product of its (nonzero) digits is 311040, while the sum is 42.

The square root of 1205664666 is about 34722.6822984631. The cubic root of 1205664666 is about 1064.3280577017.

The spelling of 1205664666 in words is "one billion, two hundred five million, six hundred sixty-four thousand, six hundred sixty-six".