66661111 has 16 divisors (see below), whose sum is σ = 76010400. Its totient is φ = 57904000.

The previous prime is 66661109. The next prime is 66661151. The reversal of 66661111 is 11116666.

It is not a de Polignac number, because 66661111 - 2¹ = 66661109 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 66661111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66661151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31185 + ... + 33253.

It is an arithmetic number, because the mean of its divisors is an integer number (4750650).

Almost surely, 2^66661111 is an apocalyptic number.

66661111 is a deficient number, since it is larger than the sum of its proper divisors (9349289).

66661111 is a wasteful number, since it uses less digits than its factorization.

With its successor (66661112) it forms an eRAP, since the sums of their prime factors are consecutive (2210 and 2211).

66661111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2210.

The product of its digits is 1296, while the sum is 28.

The square root of 66661111 is about 8164.6255884762. The cubic root of 66661111 is about 405.4688691630.

Adding to 66661111 its reverse (11116666), we get a palindrome (77777777).

It can be divided in two parts, 6666 and 1111, that added together give a palindrome (7777).

The spelling of 66661111 in words is "sixty-six million, six hundred sixty-one thousand, one hundred eleven".