111511660661 has 2 divisors, whose sum is σ = 111511660662. Its totient is φ = 111511660660.

The previous prime is 111511660639. The next prime is 111511660693. The reversal of 111511660661 is 166066115111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 93754765636 + 17756895025 = 306194^2 + 133255^2 .

It is a cyclic number.

It is not a de Polignac number, because 111511660661 - 2⁶ = 111511660597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111511660861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55755830330 + 55755830331.

It is an arithmetic number, because the mean of its divisors is an integer number (55755830331).

Almost surely, 2^111511660661 is an apocalyptic number.

It is an amenable number.

111511660661 is a deficient number, since it is larger than the sum of its proper divisors (1).

111511660661 is an equidigital number, since it uses as much as digits as its factorization.

111511660661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 35.

Adding to 111511660661 its reverse (166066115111), we get a palindrome (277577775772).

The spelling of 111511660661 in words is "one hundred eleven billion, five hundred eleven million, six hundred sixty thousand, six hundred sixty-one".