661711611 has 24 divisors (see below), whose sum is σ = 971219200. Its totient is φ = 400443120.

The previous prime is 661711597. The next prime is 661711657. The reversal of 661711611 is 116117166.

It is not a de Polignac number, because 661711611 - 2⁵ = 661711579 is a prime.

It is a super-2 number, since 2×661711611² = 875724512264430642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661711681) 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 23 ways as a sum of consecutive naturals, for example, 472290 + ... + 473688.

Almost surely, 2^661711611 is an apocalyptic number.

661711611 is a deficient number, since it is larger than the sum of its proper divisors (309507589).

661711611 is a wasteful number, since it uses less digits than its factorization.

661711611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2727 (or 2716 counting only the distinct ones).

The product of its digits is 1512, while the sum is 30.

The square root of 661711611 is about 25723.7557716598. The cubic root of 661711611 is about 871.4107604056.

Adding to 661711611 its reverse (116117166), we get a palindrome (777828777).

The spelling of 661711611 in words is "six hundred sixty-one million, seven hundred eleven thousand, six hundred eleven".