4521665221 has 4 divisors (see below), whose sum is σ = 4617870912. Its totient is φ = 4425459532.

The previous prime is 4521665191. The next prime is 4521665237. The reversal of 4521665221 is 1225661254.

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 4521665221 - 2²¹ = 4519568069 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 (4521665261) 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, 48102775 + ... + 48102868.

It is an arithmetic number, because the mean of its divisors is an integer number (1154467728).

Almost surely, 2^4521665221 is an apocalyptic number.

It is an amenable number.

4521665221 is a deficient number, since it is larger than the sum of its proper divisors (96205691).

4521665221 is an equidigital number, since it uses as much as digits as its factorization.

4521665221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96205690.

The product of its digits is 28800, while the sum is 34.

The square root of 4521665221 is about 67243.3284497429. The cubic root of 4521665221 is about 1653.6089016651.

The spelling of 4521665221 in words is "four billion, five hundred twenty-one million, six hundred sixty-five thousand, two hundred twenty-one".