66444431 has 2 divisors, whose sum is σ = 66444432. Its totient is φ = 66444430.

The previous prime is 66444421. The next prime is 66444437. The reversal of 66444431 is 13444466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66444431 - 2¹⁰ = 66443407 is a prime.

It is a super-2 number, since 2×66444431² = 8829724821827522, which contains 22 as substring.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66444437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33222215 + 33222216.

It is an arithmetic number, because the mean of its divisors is an integer number (33222216).

Almost surely, 2^66444431 is an apocalyptic number.

66444431 is a deficient number, since it is larger than the sum of its proper divisors (1).

66444431 is an equidigital number, since it uses as much as digits as its factorization.

66444431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 32.

The square root of 66444431 is about 8151.3453490820. The cubic root of 66444431 is about 405.0290707172.

Adding to 66444431 its reverse (13444466), we get a palindrome (79888897).

The spelling of 66444431 in words is "sixty-six million, four hundred forty-four thousand, four hundred thirty-one".