66270721 has 4 divisors (see below), whose sum is σ = 72295344. Its totient is φ = 60246100.

The previous prime is 66270707. The next prime is 66270731. The reversal of 66270721 is 12707266.

66270721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66270721 - 2⁷ = 66270593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66270731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3012295 + ... + 3012316.

It is an arithmetic number, because the mean of its divisors is an integer number (18073836).

Almost surely, 2^66270721 is an apocalyptic number.

It is an amenable number.

66270721 is a deficient number, since it is larger than the sum of its proper divisors (6024623).

66270721 is a wasteful number, since it uses less digits than its factorization.

66270721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6024622.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 66270721 is about 8140.6830794473. The cubic root of 66270721 is about 404.6757980576.

Adding to 66270721 its reverse (12707266), we get a palindrome (78977987).

The spelling of 66270721 in words is "sixty-six million, two hundred seventy thousand, seven hundred twenty-one".