16001666 has 8 divisors (see below), whose sum is σ = 24272460. Its totient is φ = 7910848.

The previous prime is 16001663. The next prime is 16001681. The reversal of 16001666 is 66610061.

It can be written as a sum of positive squares in 2 ways, for example, as 14100025 + 1901641 = 3755^2 + 1379^2 .

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

It is not an unprimeable number, because it can be changed into a prime (16001663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44771 + ... + 45126.

Almost surely, 2^16001666 is an apocalyptic number.

16001666 is a deficient number, since it is larger than the sum of its proper divisors (8270794).

16001666 is an equidigital number, since it uses as much as digits as its factorization.

16001666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89988.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 16001666 is about 4000.2082445793. The cubic root of 16001666 is about 251.9929556274.

The spelling of 16001666 in words is "sixteen million, one thousand, six hundred sixty-six".