66057421 has 2 divisors, whose sum is σ = 66057422. Its totient is φ = 66057420.

The previous prime is 66057391. The next prime is 66057443. The reversal of 66057421 is 12475066.

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., 56040196 + 10017225 = 7486^2 + 3165^2 .

It is a cyclic number.

It is not a de Polignac number, because 66057421 - 2¹¹ = 66055373 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66057221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33028710 + 33028711.

It is an arithmetic number, because the mean of its divisors is an integer number (33028711).

Almost surely, 2^66057421 is an apocalyptic number.

It is an amenable number.

66057421 is a deficient number, since it is larger than the sum of its proper divisors (1).

66057421 is an equidigital number, since it uses as much as digits as its factorization.

66057421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 66057421 is about 8127.5716545596. The cubic root of 66057421 is about 404.2411660923.

It can be divided in two parts, 660 and 57421, that added together give a square (58081 = 241²).

The spelling of 66057421 in words is "sixty-six million, fifty-seven thousand, four hundred twenty-one".