66511231 has 4 divisors (see below), whose sum is σ = 67638600. Its totient is φ = 65383864.

The previous prime is 66511219. The next prime is 66511241. The reversal of 66511231 is 13211566.

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 66511231 - 2¹⁵ = 66478463 is a prime.

It is a super-2 number, since 2×66511231² = 8847487698270722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66511196 and 66511205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66511241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 563596 + ... + 563713.

It is an arithmetic number, because the mean of its divisors is an integer number (16909650).

Almost surely, 2^66511231 is an apocalyptic number.

66511231 is a deficient number, since it is larger than the sum of its proper divisors (1127369).

66511231 is a wasteful number, since it uses less digits than its factorization.

66511231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1127368.

The product of its digits is 1080, while the sum is 25.

The square root of 66511231 is about 8155.4418028700. The cubic root of 66511231 is about 405.1647574340.

Adding to 66511231 its reverse (13211566), we get a palindrome (79722797).

The spelling of 66511231 in words is "sixty-six million, five hundred eleven thousand, two hundred thirty-one".