66161111 has 4 divisors (see below), whose sum is σ = 66526824. Its totient is φ = 65795400.

The previous prime is 66161107. The next prime is 66161113. The reversal of 66161111 is 11116166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66161111 - 2² = 66161107 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66161113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 182585 + ... + 182946.

It is an arithmetic number, because the mean of its divisors is an integer number (16631706).

Almost surely, 2^66161111 is an apocalyptic number.

66161111 is a deficient number, since it is larger than the sum of its proper divisors (365713).

66161111 is a wasteful number, since it uses less digits than its factorization.

66161111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365712.

The product of its digits is 216, while the sum is 23.

The square root of 66161111 is about 8133.9480573704. The cubic root of 66161111 is about 404.4525672910.

Adding to 66161111 its reverse (11116166), we get a palindrome (77277277).

The spelling of 66161111 in words is "sixty-six million, one hundred sixty-one thousand, one hundred eleven".