661688886166 has 32 divisors (see below), whose sum is σ = 1238608562688. Its totient is φ = 257558279040.

The previous prime is 661688886151. The next prime is 661688886181.

661688886166 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (661688886151) and next prime (661688886181).

It is a junction number, because it is equal to n+sod(n) for n = 661688886095 and 661688886104.

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, 1857315 + ... + 2184718.

It is an arithmetic number, because the mean of its divisors is an integer number (38706517584).

Almost surely, 2^661688886166 is an apocalyptic number.

661688886166 is a deficient number, since it is larger than the sum of its proper divisors (576919676522).

661688886166 is a wasteful number, since it uses less digits than its factorization.

661688886166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4043116.

The product of its digits is 191102976, while the sum is 70.

The spelling of 661688886166 in words is "six hundred sixty-one billion, six hundred eighty-eight million, eight hundred eighty-six thousand, one hundred sixty-six".