66403021 has 2 divisors, whose sum is σ = 66403022. Its totient is φ = 66403020.

The previous prime is 66403009. The next prime is 66403031. The reversal of 66403021 is 12030466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63202500 + 3200521 = 7950^2 + 1789^2 .

It is a cyclic number.

It is not a de Polignac number, because 66403021 - 2¹¹ = 66400973 is a prime.

It is a super-2 number, since 2×66403021² = 8818722395852882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66402983 and 66403001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66403031) 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, 33201510 + 33201511.

It is an arithmetic number, because the mean of its divisors is an integer number (33201511).

Almost surely, 2^66403021 is an apocalyptic number.

It is an amenable number.

66403021 is a deficient number, since it is larger than the sum of its proper divisors (1).

66403021 is an equidigital number, since it uses as much as digits as its factorization.

66403021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 66403021 is about 8148.8048816989. The cubic root of 66403021 is about 404.9449114727.

Adding to 66403021 its reverse (12030466), we get a palindrome (78433487).

The spelling of 66403021 in words is "sixty-six million, four hundred three thousand, twenty-one".