1665160221 has 4 divisors (see below), whose sum is σ = 2220213632. Its totient is φ = 1110106812.

The previous prime is 1665160219. The next prime is 1665160223. The reversal of 1665160221 is 1220615661.

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 an interprime number because it is at equal distance from previous prime (1665160219) and next prime (1665160223).

It is not a de Polignac number, because 1665160221 - 2¹ = 1665160219 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 (1665160223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 277526701 + ... + 277526706.

It is an arithmetic number, because the mean of its divisors is an integer number (555053408).

Almost surely, 2^1665160221 is an apocalyptic number.

It is an amenable number.

1665160221 is a deficient number, since it is larger than the sum of its proper divisors (555053411).

1665160221 is an equidigital number, since it uses as much as digits as its factorization.

1665160221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555053410.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 1665160221 is about 40806.3747593437. The cubic root of 1665160221 is about 1185.2737760498.

Adding to 1665160221 its reverse (1220615661), we get a palindrome (2885775882).

The spelling of 1665160221 in words is "one billion, six hundred sixty-five million, one hundred sixty thousand, two hundred twenty-one".