66845431 has 4 divisors (see below), whose sum is σ = 67843192. Its totient is φ = 65847672.

The previous prime is 66845399. The next prime is 66845453. The reversal of 66845431 is 13454866.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13454866 = 2 ⋅6727433.

It is a cyclic number.

It is not a de Polignac number, because 66845431 - 2⁵ = 66845399 is a prime.

It is a super-2 number, since 2×66845431² = 8936623291151522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66845491) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 498780 + ... + 498913.

It is an arithmetic number, because the mean of its divisors is an integer number (16960798).

Almost surely, 2^66845431 is an apocalyptic number.

66845431 is a deficient number, since it is larger than the sum of its proper divisors (997761).

66845431 is an equidigital number, since it uses as much as digits as its factorization.

66845431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997760.

The product of its digits is 69120, while the sum is 37.

The square root of 66845431 is about 8175.9055155989. The cubic root of 66845431 is about 405.8422365032.

It can be divided in two parts, 66845 and 431, that added together give a palindrome (67276).

The spelling of 66845431 in words is "sixty-six million, eight hundred forty-five thousand, four hundred thirty-one".