661506006601 has 16 divisors (see below), whose sum is σ = 725504532480. Its totient is φ = 598156936720.

The previous prime is 661506006587. The next prime is 661506006643. The reversal of 661506006601 is 106600605166.

It is a cyclic number.

It is not a de Polignac number, because 661506006601 - 2⁹ = 661506006089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661506009601) by changing a digit.

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, 2123046 + ... + 2414608.

It is an arithmetic number, because the mean of its divisors is an integer number (45344033280).

Almost surely, 2^661506006601 is an apocalyptic number.

It is an amenable number.

661506006601 is a deficient number, since it is larger than the sum of its proper divisors (63998525879).

661506006601 is a wasteful number, since it uses less digits than its factorization.

661506006601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292676.

The product of its (nonzero) digits is 38880, while the sum is 37.

The spelling of 661506006601 in words is "six hundred sixty-one billion, five hundred six million, six thousand, six hundred one".