66026721 has 8 divisors (see below), whose sum is σ = 91863360. Its totient is φ = 42103952.

The previous prime is 66026689. The next prime is 66026731. The reversal of 66026721 is 12762066.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66026721 - 2⁵ = 66026689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66026731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 478386 + ... + 478523.

It is an arithmetic number, because the mean of its divisors is an integer number (11482920).

Almost surely, 2^66026721 is an apocalyptic number.

It is an amenable number.

66026721 is a deficient number, since it is larger than the sum of its proper divisors (25836639).

66026721 is a wasteful number, since it uses less digits than its factorization.

66026721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 956935.

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 66026721 is about 8125.6828020789. The cubic root of 66026721 is about 404.1785330747.

Adding to 66026721 its reverse (12762066), we get a palindrome (78788787).

The spelling of 66026721 in words is "sixty-six million, twenty-six thousand, seven hundred twenty-one".