661013515 has 16 divisors (see below), whose sum is σ = 836363520. Its totient is φ = 500139360.

The previous prime is 661013503. The next prime is 661013519. The reversal of 661013515 is 515310166.

It is a de Polignac number, because none of the positive numbers 2^k-661013515 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661013519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54432 + ... + 65458.

It is an arithmetic number, because the mean of its divisors is an integer number (52272720).

Almost surely, 2^661013515 is an apocalyptic number.

661013515 is a deficient number, since it is larger than the sum of its proper divisors (175350005).

661013515 is a wasteful number, since it uses less digits than its factorization.

661013515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11682.

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 661013515 is about 25710.1830993091. The cubic root of 661013515 is about 871.1042107409.

The spelling of 661013515 in words is "six hundred sixty-one million, thirteen thousand, five hundred fifteen".