221421173 has 2 divisors, whose sum is σ = 221421174. Its totient is φ = 221421172.

The previous prime is 221421169. The next prime is 221421241. The reversal of 221421173 is 371124122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 182196004 + 39225169 = 13498^2 + 6263^2 .

It is a cyclic number.

It is not a de Polignac number, because 221421173 - 2² = 221421169 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221421113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110710586 + 110710587.

It is an arithmetic number, because the mean of its divisors is an integer number (110710587).

Almost surely, 2^221421173 is an apocalyptic number.

It is an amenable number.

221421173 is a deficient number, since it is larger than the sum of its proper divisors (1).

221421173 is an equidigital number, since it uses as much as digits as its factorization.

221421173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 672, while the sum is 23.

The square root of 221421173 is about 14880.2275856252. The cubic root of 221421173 is about 604.9781864958.

Adding to 221421173 its reverse (371124122), we get a palindrome (592545295).

The spelling of 221421173 in words is "two hundred twenty-one million, four hundred twenty-one thousand, one hundred seventy-three".