66311231 has 16 divisors (see below), whose sum is σ = 80206848. Its totient is φ = 53592000.

The previous prime is 66311207. The next prime is 66311239. The reversal of 66311231 is 13211366.

It is a happy number.

It is not a de Polignac number, because 66311231 - 2¹⁴ = 66294847 is a prime.

It is a super-2 number, since 2×66311231² = 8794358713470722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66311197 and 66311206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66311239) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8531 + ... + 14331.

It is an arithmetic number, because the mean of its divisors is an integer number (5012928).

Almost surely, 2^66311231 is an apocalyptic number.

66311231 is a deficient number, since it is larger than the sum of its proper divisors (13895617).

66311231 is a wasteful number, since it uses less digits than its factorization.

66311231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5902.

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

The square root of 66311231 is about 8143.1708197728. The cubic root of 66311231 is about 404.7582380710.

Adding to 66311231 its reverse (13211366), we get a palindrome (79522597).

The spelling of 66311231 in words is "sixty-six million, three hundred eleven thousand, two hundred thirty-one".