66231631 has 2 divisors, whose sum is σ = 66231632. Its totient is φ = 66231630.

The previous prime is 66231629. The next prime is 66231647. The reversal of 66231631 is 13613266.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66231631 - 2¹ = 66231629 is a prime.

It is a super-2 number, since 2×66231631² = 8773257889840322, which contains 22 as substring.

Together with 66231629, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 66231631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66231731) 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, 33115815 + 33115816.

It is an arithmetic number, because the mean of its divisors is an integer number (33115816).

Almost surely, 2^66231631 is an apocalyptic number.

66231631 is a deficient number, since it is larger than the sum of its proper divisors (1).

66231631 is an equidigital number, since it uses as much as digits as its factorization.

66231631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 28.

The square root of 66231631 is about 8138.2818211217. The cubic root of 66231631 is about 404.5962159637.

Adding to 66231631 its reverse (13613266), we get a palindrome (79844897).

The spelling of 66231631 in words is "sixty-six million, two hundred thirty-one thousand, six hundred thirty-one".