66111005501 has 4 divisors (see below), whose sum is σ = 66123971004. Its totient is φ = 66098040000.

The previous prime is 66111005497. The next prime is 66111005507. The reversal of 66111005501 is 10550011166.

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

It can be written as a sum of positive squares in 2 ways, for example, as 25961265625 + 40149739876 = 161125^2 + 200374^2 .

It is a cyclic number.

It is not a de Polignac number, because 66111005501 - 2² = 66111005497 is a prime.

It is a super-3 number, since 3×66111005501³ (a number of 33 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66111005507) 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, 6475100 + ... + 6485301.

It is an arithmetic number, because the mean of its divisors is an integer number (16530992751).

Almost surely, 2^66111005501 is an apocalyptic number.

It is an amenable number.

66111005501 is a deficient number, since it is larger than the sum of its proper divisors (12965503).

66111005501 is a wasteful number, since it uses less digits than its factorization.

66111005501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12965502.

The product of its (nonzero) digits is 900, while the sum is 26.

Adding to 66111005501 its reverse (10550011166), we get a palindrome (76661016667).

The spelling of 66111005501 in words is "sixty-six billion, one hundred eleven million, five thousand, five hundred one".