66131231 has 2 divisors, whose sum is σ = 66131232. Its totient is φ = 66131230.

The previous prime is 66131203. The next prime is 66131239. The reversal of 66131231 is 13213166.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66131231 is a prime.

It is a super-2 number, since 2×66131231² = 8746679427150722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66131197 and 66131206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66131239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33065615 + 33065616.

It is an arithmetic number, because the mean of its divisors is an integer number (33065616).

Almost surely, 2^66131231 is an apocalyptic number.

66131231 is a deficient number, since it is larger than the sum of its proper divisors (1).

66131231 is an equidigital number, since it uses as much as digits as its factorization.

66131231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 23.

The square root of 66131231 is about 8132.1111035204. Note that the first 4 decimals coincide. The cubic root of 66131231 is about 404.3916711831.

Adding to 66131231 its reverse (13213166), we get a palindrome (79344397).

The spelling of 66131231 in words is "sixty-six million, one hundred thirty-one thousand, two hundred thirty-one".