163556321 has 2 divisors, whose sum is σ = 163556322. Its totient is φ = 163556320.

The previous prime is 163556291. The next prime is 163556329. The reversal of 163556321 is 123655361.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135466321 + 28090000 = 11639^2 + 5300^2 .

It is an emirp because it is prime and its reverse (123655361) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 163556321 - 2²² = 159362017 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (163556329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81778160 + 81778161.

It is an arithmetic number, because the mean of its divisors is an integer number (81778161).

Almost surely, 2^163556321 is an apocalyptic number.

It is an amenable number.

163556321 is a deficient number, since it is larger than the sum of its proper divisors (1).

163556321 is an equidigital number, since it uses as much as digits as its factorization.

163556321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16200, while the sum is 32.

The square root of 163556321 is about 12788.9139882947. The cubic root of 163556321 is about 546.8763104230.

The spelling of 163556321 in words is "one hundred sixty-three million, five hundred fifty-six thousand, three hundred twenty-one".