661166111 has 4 divisors (see below), whose sum is σ = 661503192. Its totient is φ = 660829032.

The previous prime is 661166101. The next prime is 661166141. The reversal of 661166111 is 111661166.

661166111 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661166111 is a prime.

It is a Duffinian number.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661166101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165581 + ... + 169526.

It is an arithmetic number, because the mean of its divisors is an integer number (165375798).

Almost surely, 2^661166111 is an apocalyptic number.

661166111 is a deficient number, since it is larger than the sum of its proper divisors (337081).

661166111 is a wasteful number, since it uses less digits than its factorization.

661166111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337080.

The product of its digits is 1296, while the sum is 29.

The square root of 661166111 is about 25713.1505459755. The cubic root of 661166111 is about 871.1712375049.

It can be divided in two parts, 66116 and 6111, that added together give a palindrome (72227).

The spelling of 661166111 in words is "six hundred sixty-one million, one hundred sixty-six thousand, one hundred eleven".