66450021 has 16 divisors (see below), whose sum is σ = 97616448. Its totient is φ = 39872000.

The previous prime is 66450017. The next prime is 66450023. The reversal of 66450021 is 12005466.

It is a cyclic number.

It is not a de Polignac number, because 66450021 - 2² = 66450017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66449973 and 66450000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66450023) 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 in 15 ways as a sum of consecutive naturals, for example, 6636 + ... + 13301.

It is an arithmetic number, because the mean of its divisors is an integer number (6101028).

Almost surely, 2^66450021 is an apocalyptic number.

It is an amenable number.

66450021 is a deficient number, since it is larger than the sum of its proper divisors (31166427).

66450021 is a wasteful number, since it uses less digits than its factorization.

66450021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20052.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 66450021 is about 8151.6882300539. The cubic root of 66450021 is about 405.0404288249.

Adding to 66450021 its reverse (12005466), we get a palindrome (78455487).

The spelling of 66450021 in words is "sixty-six million, four hundred fifty thousand, twenty-one".