66257221 has 8 divisors (see below), whose sum is σ = 67317120. Its totient is φ = 65203008.

The previous prime is 66257179. The next prime is 66257239. The reversal of 66257221 is 12275266.

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 66257221 - 2¹¹ = 66255173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66257251) 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, 26205 + ... + 28621.

It is an arithmetic number, because the mean of its divisors is an integer number (8414640).

Almost surely, 2^66257221 is an apocalyptic number.

It is an amenable number.

66257221 is a deficient number, since it is larger than the sum of its proper divisors (1059899).

66257221 is a wasteful number, since it uses less digits than its factorization.

66257221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2843.

The product of its digits is 10080, while the sum is 31.

The square root of 66257221 is about 8139.8538684672. The cubic root of 66257221 is about 404.6483173733.

The spelling of 66257221 in words is "sixty-six million, two hundred fifty-seven thousand, two hundred twenty-one".