661110101 has 4 divisors (see below), whose sum is σ = 661161792. Its totient is φ = 661058412.

The previous prime is 661110031. The next prime is 661110143. The reversal of 661110101 is 101011166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661110101 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661110101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661110701) 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 3 ways as a sum of consecutive naturals, for example, 8996 + ... + 37458.

It is an arithmetic number, because the mean of its divisors is an integer number (165290448).

Almost surely, 2^661110101 is an apocalyptic number.

It is an amenable number.

661110101 is a deficient number, since it is larger than the sum of its proper divisors (51691).

661110101 is a wasteful number, since it uses less digits than its factorization.

661110101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51690.

The product of its (nonzero) digits is 36, while the sum is 17.

The square root of 661110101 is about 25712.0613914948. The cubic root of 661110101 is about 871.1466366882.

Adding to 661110101 its reverse (101011166), we get a palindrome (762121267).

The spelling of 661110101 in words is "six hundred sixty-one million, one hundred ten thousand, one hundred one".