1601616666 has 32 divisors (see below), whose sum is σ = 3631199040. Its totient is φ = 466867584.

The previous prime is 1601616659. The next prime is 1601616689. The reversal of 1601616666 is 6666161061.

It is a happy number.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon 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, 538875 + ... + 541838.

It is an arithmetic number, because the mean of its divisors is an integer number (113474970).

Almost surely, 2^1601616666 is an apocalyptic number.

1601616666 is an abundant number, since it is smaller than the sum of its proper divisors (2029582374).

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

1601616666 is a wasteful number, since it uses less digits than its factorization.

1601616666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1080750.

The product of its (nonzero) digits is 46656, while the sum is 39.

The square root of 1601616666 is about 40020.2032228723. The cubic root of 1601616666 is about 1170.0008926869. Note that the first 3 decimals are identical.

The spelling of 1601616666 in words is "one billion, six hundred one million, six hundred sixteen thousand, six hundred sixty-six".