661166611 has 8 divisors (see below), whose sum is σ = 756354560. Its totient is φ = 566162568.

The previous prime is 661166609. The next prime is 661166633. The reversal of 661166611 is 116661166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661166611 - 2¹ = 661166609 is a prime.

It is a Duffinian number.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (661166651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38181 + ... + 52726.

It is an arithmetic number, because the mean of its divisors is an integer number (94544320).

Almost surely, 2^661166611 is an apocalyptic number.

661166611 is the 14846-th hex number.

661166611 is a deficient number, since it is larger than the sum of its proper divisors (95187949).

661166611 is a wasteful number, since it uses less digits than its factorization.

661166611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91953.

The product of its digits is 7776, while the sum is 34.

The square root of 661166611 is about 25713.1602686251. The cubic root of 661166611 is about 871.1714571096.

Subtracting from 661166611 its reverse (116661166), we obtain a palindrome (544505445).

It can be divided in two parts, 66116 and 6611, that added together give a palindrome (72727).

The spelling of 661166611 in words is "six hundred sixty-one million, one hundred sixty-six thousand, six hundred eleven".