664180221 has 16 divisors (see below), whose sum is σ = 900218880. Its totient is φ = 435494640.

The previous prime is 664180201. The next prime is 664180241. The reversal of 664180221 is 122081466.

It is an interprime number because it is at equal distance from previous prime (664180201) and next prime (664180241).

It is not a de Polignac number, because 664180221 - 2¹⁸ = 663918077 is a prime.

It is a super-2 number, since 2×664180221² = 882270731935217682, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664180201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89956 + ... + 97058.

It is an arithmetic number, because the mean of its divisors is an integer number (56263680).

Almost surely, 2^664180221 is an apocalyptic number.

It is an amenable number.

664180221 is a deficient number, since it is larger than the sum of its proper divisors (236038659).

664180221 is a wasteful number, since it uses less digits than its factorization.

664180221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7616.

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 664180221 is about 25771.6941817957. The cubic root of 664180221 is about 872.4930565425.

The spelling of 664180221 in words is "six hundred sixty-four million, one hundred eighty thousand, two hundred twenty-one".