1666500215 has 4 divisors (see below), whose sum is σ = 1999800264. Its totient is φ = 1333200168.

The previous prime is 1666500163. The next prime is 1666500229. The reversal of 1666500215 is 5120056661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1666500215 - 2¹⁸ = 1666238071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166650017 + ... + 166650026.

It is an arithmetic number, because the mean of its divisors is an integer number (499950066).

Almost surely, 2^1666500215 is an apocalyptic number.

1666500215 is a deficient number, since it is larger than the sum of its proper divisors (333300049).

1666500215 is an equidigital number, since it uses as much as digits as its factorization.

1666500215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333300048.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 1666500215 is about 40822.7903872335. The cubic root of 1666500215 is about 1185.5916301281.

Adding to 1666500215 its reverse (5120056661), we get a palindrome (6786556876).

The spelling of 1666500215 in words is "one billion, six hundred sixty-six million, five hundred thousand, two hundred fifteen".