66437621 has 2 divisors, whose sum is σ = 66437622. Its totient is φ = 66437620.

The previous prime is 66437603. The next prime is 66437627. The reversal of 66437621 is 12673466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65836996 + 600625 = 8114^2 + 775^2 .

It is a cyclic number.

It is not a de Polignac number, because 66437621 - 2¹⁴ = 66421237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66437627) 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, 33218810 + 33218811.

It is an arithmetic number, because the mean of its divisors is an integer number (33218811).

Almost surely, 2^66437621 is an apocalyptic number.

It is an amenable number.

66437621 is a deficient number, since it is larger than the sum of its proper divisors (1).

66437621 is an equidigital number, since it uses as much as digits as its factorization.

66437621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 35.

The square root of 66437621 is about 8150.9276159220. The cubic root of 66437621 is about 405.0152328772.

The spelling of 66437621 in words is "sixty-six million, four hundred thirty-seven thousand, six hundred twenty-one".