163221997 has 4 divisors (see below), whose sum is σ = 164904796. Its totient is φ = 161539200.

The previous prime is 163221967. The next prime is 163222009. The reversal of 163221997 is 799122361.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45846441 + 117375556 = 6771^2 + 10834^2 .

It is a cyclic number.

It is not a de Polignac number, because 163221997 - 2¹¹ = 163219949 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 (163221917) 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, 841254 + ... + 841447.

It is an arithmetic number, because the mean of its divisors is an integer number (41226199).

Almost surely, 2^163221997 is an apocalyptic number.

It is an amenable number.

163221997 is a deficient number, since it is larger than the sum of its proper divisors (1682799).

163221997 is an equidigital number, since it uses as much as digits as its factorization.

163221997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1682798.

The product of its digits is 40824, while the sum is 40.

The square root of 163221997 is about 12775.8364501116. The cubic root of 163221997 is about 546.5034345995.

The spelling of 163221997 in words is "one hundred sixty-three million, two hundred twenty-one thousand, nine hundred ninety-seven".