661115606165 has 16 divisors (see below), whose sum is σ = 906690074112. Its totient is φ = 453327794304.

The previous prime is 661115606149. The next prime is 661115606197. The reversal of 661115606165 is 561606511166.

It is not a de Polignac number, because 661115606165 - 2⁴ = 661115606149 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2091572 + ... + 2386818.

It is an arithmetic number, because the mean of its divisors is an integer number (56668129632).

Almost surely, 2^661115606165 is an apocalyptic number.

It is an amenable number.

661115606165 is a deficient number, since it is larger than the sum of its proper divisors (245574467947).

661115606165 is a wasteful number, since it uses less digits than its factorization.

661115606165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359236.

The product of its (nonzero) digits is 194400, while the sum is 44.

The spelling of 661115606165 in words is "six hundred sixty-one billion, one hundred fifteen million, six hundred six thousand, one hundred sixty-five".