66675421 has 2 divisors, whose sum is σ = 66675422. Its totient is φ = 66675420.

The previous prime is 66675383. The next prime is 66675449. The reversal of 66675421 is 12457666.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66504025 + 171396 = 8155^2 + 414^2 .

It is a cyclic number.

It is not a de Polignac number, because 66675421 - 2⁷ = 66675293 is a prime.

It is a super-2 number, since 2×66675421² = 8891223531054482, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66675481) 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, 33337710 + 33337711.

It is an arithmetic number, because the mean of its divisors is an integer number (33337711).

Almost surely, 2^66675421 is an apocalyptic number.

It is an amenable number.

66675421 is a deficient number, since it is larger than the sum of its proper divisors (1).

66675421 is an equidigital number, since it uses as much as digits as its factorization.

66675421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 37.

The square root of 66675421 is about 8165.5018829218. The cubic root of 66675421 is about 405.4978808026.

The spelling of 66675421 in words is "sixty-six million, six hundred seventy-five thousand, four hundred twenty-one".