66631331 has 4 divisors (see below), whose sum is σ = 71756832. Its totient is φ = 61505832.

The previous prime is 66631319. The next prime is 66631343. The reversal of 66631331 is 13313666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13313666 = 2 ⋅6656833.

It is an interprime number because it is at equal distance from previous prime (66631319) and next prime (66631343).

It is a cyclic number.

It is not a de Polignac number, because 66631331 - 2¹⁰ = 66630307 is a prime.

It is a super-2 number, since 2×66631331² = 8879468541663122, 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 = 66631294 and 66631303.

It is not an unprimeable number, because it can be changed into a prime (66636331) 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, 2562731 + ... + 2562756.

It is an arithmetic number, because the mean of its divisors is an integer number (17939208).

Almost surely, 2^66631331 is an apocalyptic number.

66631331 is a deficient number, since it is larger than the sum of its proper divisors (5125501).

66631331 is a wasteful number, since it uses less digits than its factorization.

66631331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5125500.

The product of its digits is 5832, while the sum is 29.

The square root of 66631331 is about 8162.8016636447. The cubic root of 66631331 is about 405.4084808232.

Adding to 66631331 its reverse (13313666), we get a palindrome (79944997).

The spelling of 66631331 in words is "sixty-six million, six hundred thirty-one thousand, three hundred thirty-one".