1665561015 has 16 divisors (see below), whose sum is σ = 2960997600. Its totient is φ = 888299136.

The previous prime is 1665561013. The next prime is 1665561049. The reversal of 1665561015 is 5101655661.

It is not a de Polignac number, because 1665561015 - 2¹ = 1665561013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665561013) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 6168610 + ... + 6168879.

It is an arithmetic number, because the mean of its divisors is an integer number (185062350).

Almost surely, 2^1665561015 is an apocalyptic number.

1665561015 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1665561015 is a deficient number, since it is larger than the sum of its proper divisors (1295436585).

1665561015 is a wasteful number, since it uses less digits than its factorization.

1665561015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12337503 (or 12337497 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 36.

The square root of 1665561015 is about 40811.2853877454. The cubic root of 1665561015 is about 1185.3688644989.

The spelling of 1665561015 in words is "one billion, six hundred sixty-five million, five hundred sixty-one thousand, fifteen".