660864515 has 4 divisors (see below), whose sum is σ = 793037424. Its totient is φ = 528691608.

The previous prime is 660864461. The next prime is 660864539. The reversal of 660864515 is 515468066.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 515468066 = 2 ⋅257734033.

It is a cyclic number.

It is not a de Polignac number, because 660864515 - 2¹² = 660860419 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 (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66086447 + ... + 66086456.

It is an arithmetic number, because the mean of its divisors is an integer number (198259356).

Almost surely, 2^660864515 is an apocalyptic number.

660864515 is a deficient number, since it is larger than the sum of its proper divisors (132172909).

660864515 is a wasteful number, since it uses less digits than its factorization.

660864515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132172908.

The product of its (nonzero) digits is 172800, while the sum is 41.

The square root of 660864515 is about 25707.2852514613. The cubic root of 660864515 is about 871.0387535412.

The spelling of 660864515 in words is "six hundred sixty million, eight hundred sixty-four thousand, five hundred fifteen".