661011515 has 16 divisors (see below), whose sum is σ = 810293760. Its totient is φ = 517503840.

The previous prime is 661011509. The next prime is 661011557. The reversal of 661011515 is 515110166.

It is not a de Polignac number, because 661011515 - 2⁸ = 661011259 is a prime.

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 15 ways as a sum of consecutive naturals, for example, 62030 + ... + 71900.

It is an arithmetic number, because the mean of its divisors is an integer number (50643360).

Almost surely, 2^661011515 is an apocalyptic number.

661011515 is a deficient number, since it is larger than the sum of its proper divisors (149282245).

661011515 is a wasteful number, since it uses less digits than its factorization.

661011515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10162.

The product of its (nonzero) digits is 900, while the sum is 26.

The square root of 661011515 is about 25710.1442041852. The cubic root of 661011515 is about 871.1033321859.

The spelling of 661011515 in words is "six hundred sixty-one million, eleven thousand, five hundred fifteen".