1516505665 has 4 divisors (see below), whose sum is σ = 1819806804. Its totient is φ = 1213204528.

The previous prime is 1516505659. The next prime is 1516505677. The reversal of 1516505665 is 5665056151.

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

It can be written as a sum of positive squares in 2 ways, for example, as 496086529 + 1020419136 = 22273^2 + 31944^2 .

It is a cyclic number.

It is not a de Polignac number, because 1516505665 - 2⁵ = 1516505633 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151650562 + ... + 151650571.

It is an arithmetic number, because the mean of its divisors is an integer number (454951701).

Almost surely, 2^1516505665 is an apocalyptic number.

It is an amenable number.

1516505665 is a deficient number, since it is larger than the sum of its proper divisors (303301139).

1516505665 is an equidigital number, since it uses as much as digits as its factorization.

1516505665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303301138.

The product of its (nonzero) digits is 135000, while the sum is 40.

The square root of 1516505665 is about 38942.3376930559. The cubic root of 1516505665 is about 1148.8976620228.

The spelling of 1516505665 in words is "one billion, five hundred sixteen million, five hundred five thousand, six hundred sixty-five".