1565163221 has 4 divisors (see below), whose sum is σ = 1565362944. Its totient is φ = 1564963500.

The previous prime is 1565163217. The next prime is 1565163253. The reversal of 1565163221 is 1223615651.

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 1565163221 - 2² = 1565163217 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 (1565163211) 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 3 ways as a sum of consecutive naturals, for example, 87605 + ... + 103946.

It is an arithmetic number, because the mean of its divisors is an integer number (391340736).

Almost surely, 2^1565163221 is an apocalyptic number.

It is an amenable number.

1565163221 is a deficient number, since it is larger than the sum of its proper divisors (199723).

1565163221 is an equidigital number, since it uses as much as digits as its factorization.

1565163221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199722.

The product of its digits is 10800, while the sum is 32.

The square root of 1565163221 is about 39562.1437867060. The cubic root of 1565163221 is about 1161.0561182816.

Adding to 1565163221 its reverse (1223615651), we get a palindrome (2788778872).

The spelling of 1565163221 in words is "one billion, five hundred sixty-five million, one hundred sixty-three thousand, two hundred twenty-one".