661041111 has 8 divisors (see below), whose sum is σ = 892545280. Its totient is φ = 435115512.

The previous prime is 661041097. The next prime is 661041119. The reversal of 661041111 is 111140166.

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

It is not a de Polignac number, because 661041111 - 2⁶ = 661041047 is a prime.

It is a super-2 number, since 2×661041111² = 873950700864228642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661041119) 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, 1394365 + ... + 1394838.

It is an arithmetic number, because the mean of its divisors is an integer number (111568160).

Almost surely, 2^661041111 is an apocalyptic number.

661041111 is a deficient number, since it is larger than the sum of its proper divisors (231504169).

661041111 is a wasteful number, since it uses less digits than its factorization.

661041111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2789285.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 661041111 is about 25710.7197682212. The cubic root of 661041111 is about 871.1163328618.

Adding to 661041111 its reverse (111140166), we get a palindrome (772181277).

The spelling of 661041111 in words is "six hundred sixty-one million, forty-one thousand, one hundred eleven".