221317121 has 2 divisors, whose sum is σ = 221317122. Its totient is φ = 221317120.

The previous prime is 221317099. The next prime is 221317123. The reversal of 221317121 is 121713122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 145540096 + 75777025 = 12064^2 + 8705^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221317121 is a prime.

Together with 221317123, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 221317093 and 221317102.

It is not a weakly prime, because it can be changed into another prime (221317123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110658560 + 110658561.

It is an arithmetic number, because the mean of its divisors is an integer number (110658561).

Almost surely, 2^221317121 is an apocalyptic number.

It is an amenable number.

221317121 is a deficient number, since it is larger than the sum of its proper divisors (1).

221317121 is an equidigital number, since it uses as much as digits as its factorization.

221317121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 168, while the sum is 20.

The square root of 221317121 is about 14876.7308572818. The cubic root of 221317121 is about 604.8834062594.

The spelling of 221317121 in words is "two hundred twenty-one million, three hundred seventeen thousand, one hundred twenty-one".