661115517 has 16 divisors (see below), whose sum is σ = 914661888. Its totient is φ = 424304640.

The previous prime is 661115509. The next prime is 661115551. The reversal of 661115517 is 715511166.

It is not a de Polignac number, because 661115517 - 2³ = 661115509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661115017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 468 + ... + 36365.

It is an arithmetic number, because the mean of its divisors is an integer number (57166368).

Almost surely, 2^661115517 is an apocalyptic number.

It is an amenable number.

661115517 is a deficient number, since it is larger than the sum of its proper divisors (253546371).

661115517 is a wasteful number, since it uses less digits than its factorization.

661115517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37060.

The product of its digits is 6300, while the sum is 33.

The square root of 661115517 is about 25712.1667115006. The cubic root of 661115517 is about 871.1490155745.

The spelling of 661115517 in words is "six hundred sixty-one million, one hundred fifteen thousand, five hundred seventeen".