66424381 has 2 divisors, whose sum is σ = 66424382. Its totient is φ = 66424380.

The previous prime is 66424357. The next prime is 66424411. The reversal of 66424381 is 18342466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40322500 + 26101881 = 6350^2 + 5109^2 .

It is a cyclic number.

It is not a de Polignac number, because 66424381 - 2²¹ = 64327229 is a prime.

It is a super-2 number, since 2×66424381² = 8824396782466322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66424081) 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, 33212190 + 33212191.

It is an arithmetic number, because the mean of its divisors is an integer number (33212191).

Almost surely, 2^66424381 is an apocalyptic number.

It is an amenable number.

66424381 is a deficient number, since it is larger than the sum of its proper divisors (1).

66424381 is an equidigital number, since it uses as much as digits as its factorization.

66424381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 34.

The square root of 66424381 is about 8150.1153979560. The cubic root of 66424381 is about 404.9883266462.

The spelling of 66424381 in words is "sixty-six million, four hundred twenty-four thousand, three hundred eighty-one".