66611855 has 8 divisors (see below), whose sum is σ = 80166672. Its totient is φ = 53134528.

The previous prime is 66611849. The next prime is 66611873. The reversal of 66611855 is 55811666.

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

It is a cyclic number.

It is not a de Polignac number, because 66611855 - 2¹² = 66607759 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17462 + ... + 20931.

It is an arithmetic number, because the mean of its divisors is an integer number (10020834).

Almost surely, 2^66611855 is an apocalyptic number.

66611855 is a deficient number, since it is larger than the sum of its proper divisors (13554817).

66611855 is a wasteful number, since it uses less digits than its factorization.

66611855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38745.

The product of its digits is 43200, while the sum is 38.

The square root of 66611855 is about 8161.6086037006. The cubic root of 66611855 is about 405.3689773601.

It can be divided in two parts, 666 and 11855, that added together give a palindrome (12521).

The spelling of 66611855 in words is "sixty-six million, six hundred eleven thousand, eight hundred fifty-five".