66111631 has 2 divisors, whose sum is σ = 66111632. Its totient is φ = 66111630.

The previous prime is 66111599. The next prime is 66111673. The reversal of 66111631 is 13611166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66111631 - 2⁵ = 66111599 is a prime.

It is a super-2 number, since 2×66111631² = 8741495506960322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66111596 and 66111605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66171631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33055815 + 33055816.

It is an arithmetic number, because the mean of its divisors is an integer number (33055816).

Almost surely, 2^66111631 is an apocalyptic number.

66111631 is a deficient number, since it is larger than the sum of its proper divisors (1).

66111631 is an equidigital number, since it uses as much as digits as its factorization.

66111631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 25.

The square root of 66111631 is about 8130.9059150872. The cubic root of 66111631 is about 404.3517159819.

Adding to 66111631 its reverse (13611166), we get a palindrome (79722797).

The spelling of 66111631 in words is "sixty-six million, one hundred eleven thousand, six hundred thirty-one".