1221098173 has 2 divisors, whose sum is σ = 1221098174. Its totient is φ = 1221098172.

The previous prime is 1221098159. The next prime is 1221098209. The reversal of 1221098173 is 3718901221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 806446404 + 414651769 = 28398^2 + 20363^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221098173 - 2⁵ = 1221098141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221098113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610549086 + 610549087.

It is an arithmetic number, because the mean of its divisors is an integer number (610549087).

Almost surely, 2^1221098173 is an apocalyptic number.

It is an amenable number.

1221098173 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221098173 is an equidigital number, since it uses as much as digits as its factorization.

1221098173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 1221098173 is about 34944.2151578770. The cubic root of 1221098173 is about 1068.8502434250.

Adding to 1221098173 its reverse (3718901221), we get a palindrome (4939999394).

The spelling of 1221098173 in words is "one billion, two hundred twenty-one million, ninety-eight thousand, one hundred seventy-three".