66042421 has 2 divisors, whose sum is σ = 66042422. Its totient is φ = 66042420.

The previous prime is 66042419. The next prime is 66042451. The reversal of 66042421 is 12424066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38068900 + 27973521 = 6170^2 + 5289^2 .

It is a cyclic number.

It is not a de Polignac number, because 66042421 - 2¹ = 66042419 is a prime.

Together with 66042419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66042401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33021210 + 33021211.

It is an arithmetic number, because the mean of its divisors is an integer number (33021211).

Almost surely, 2^66042421 is an apocalyptic number.

It is an amenable number.

66042421 is a deficient number, since it is larger than the sum of its proper divisors (1).

66042421 is an equidigital number, since it uses as much as digits as its factorization.

66042421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 66042421 is about 8126.6488173170. The cubic root of 66042421 is about 404.2105660657.

Adding to 66042421 its reverse (12424066), we get a palindrome (78466487).

It can be divided in two parts, 6604 and 2421, that added together give a square (9025 = 95²).

The spelling of 66042421 in words is "sixty-six million, forty-two thousand, four hundred twenty-one".