66231731 has 2 divisors, whose sum is σ = 66231732. Its totient is φ = 66231730.

The previous prime is 66231721. The next prime is 66231757. The reversal of 66231731 is 13713266.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66231731 is a prime.

It is a super-2 number, since 2×66231731² = 8773284382512722, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 66231694 and 66231703.

It is not a weakly prime, because it can be changed into another prime (66231721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33115865 + 33115866.

It is an arithmetic number, because the mean of its divisors is an integer number (33115866).

Almost surely, 2^66231731 is an apocalyptic number.

66231731 is a deficient number, since it is larger than the sum of its proper divisors (1).

66231731 is an equidigital number, since it uses as much as digits as its factorization.

66231731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4536, while the sum is 29.

The square root of 66231731 is about 8138.2879649224. The cubic root of 66231731 is about 404.5964195905.

Adding to 66231731 its reverse (13713266), we get a palindrome (79944997).

The spelling of 66231731 in words is "sixty-six million, two hundred thirty-one thousand, seven hundred thirty-one".