1665666515 has 8 divisors (see below), whose sum is σ = 1999990608. Its totient is φ = 1331739360.

The previous prime is 1665666503. The next prime is 1665666553. The reversal of 1665666515 is 5156665661.

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

It is not a de Polignac number, because 1665666515 - 2¹² = 1665662419 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1665666515.

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, 89921 + ... + 106850.

It is an arithmetic number, because the mean of its divisors is an integer number (249998826).

Almost surely, 2^1665666515 is an apocalyptic number.

1665666515 is a deficient number, since it is larger than the sum of its proper divisors (334324093).

1665666515 is a wasteful number, since it uses less digits than its factorization.

1665666515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198469.

The product of its digits is 972000, while the sum is 47.

The square root of 1665666515 is about 40812.5779019165. The cubic root of 1665666515 is about 1185.3938918568.

The spelling of 1665666515 in words is "one billion, six hundred sixty-five million, six hundred sixty-six thousand, five hundred fifteen".